Advice on buying a 35i or 35is

D

db_

New member
 Cambridge
Hi, I'm looking to buy a 35i or a 35is (need a car for a short, in city, commute and decided it might as well be a fun one).

Currently considering this one from auto-trader: 35i DCT
Here's how I'm looking at it:
Positives:
1. I like the color and the spec. Idrive is a must for me so I can install a carplay adapter.
2. I think the adaptive suspension is a plus as I'm planning to use this as my daily driver for a 5 miles commute in Cambridge.
3. Doesn't seem to have any rust in the trunk.
4. Relatively cheap (and I might be able to get it at a lower price as the price was already reduced by 500pounds last week) so I can spend some money on servicing it/preventative maintenance.

Negatives:
1. No preventative maintenance. Nothing for the roof, no indication that the adaptive suspension has been checked or replaced.
2. Some servicing done recently (ABS pump cleaned, plugs and pins refreshed, smoke test, engine purge valve replaced). This sounds to me like the car was throwing some errors and they were addressed but not necessarily in a thorough way.

This is a private seller and this would be my first car bought in the UK so I would appreciate some advice:
1. Any red flags with this car?
2. If no red flags any recommendations for a specialist around North London for a pre-purchase inspection and what should I pay attention to?
3. Do I just buy James' car z4 buy vehicles and try to somehow retrofit a carplay display(not recommended from what I could gather from the forum)? I would really like to have the option to hide the display as I love the look of the dashboard with the screen closed.
4. Extra question: how bad is the DCT in traffic? Is it a no go or just a possible annoyance?

Thanks in advance for any help with the questions above.
 
Why do you want a 306bhp car for a 5 mile commute in traffic db…? This is completely the wrong car for that task and won’t do it any good at all if that’s all it’s going to be used for, it won’t even get up to temperature for starters, the turbos won’t be boosting, the impeller oil seals won’t get the proper heat cycles through them so will perish, the wastegates won’t be opening and closing properly so they’ll seize up, et, etc,

Anyway, if it’s a must then the car you show looks fine imo, the 35i came with or without adaptive suspension depending on customer spec, roof maintenance really is down to changing the salmon relays, a very easy inexpensive job, other than that really it’s down to sorting a problem when it arises.

Check the boot for water ingress as the rear light seals can perish.

If it has got adaptive shocks check for oil leaks, they’re very expensive to replace.

This car you show has service history, if the normal car buying checks are good then I don’t see any particular issues, not meaning to be critical but what more do you expect than that..?

The DCT is a very good gearbox, some say it’s a bit clunky but I don’t agree for what it’s worth.

Imo you’d be much better off with a non turbo car for a commute, you’re wasting fuel money and you’ll get issues with a 35i for this job. But obvs your call. 👍

I’ve kept this short as soon you’ll get chapter, verse, a book, a lecture and then some thrown at you…like it or not…! 😆
 
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The DCT is brilliant in traffic. The AS is rubbish. Look up Robbie’s roof preventive maintenance tips.

Oh, I’ve a book for you.
:rofl:
 
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Welcome 🙂
Lovely car, and a sensible price.
But you really need to be regularly taking this for longer runs or you will create problems with 5 mile drives as John-e89 has stated.

These are GT cars (with sporty ideas) and really come into their own on longer drives.
Buy it then take a drive up the east coast to Northumberland and you will really understand what these are about 😊

Oh and good luck with the lengthy advice you will be given soon enough from one of our Scottish brethren 😋
 
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Oh and good luck with the lengthy advice you will be given soon enough from one of our Scottish brethren 😋
Click to expand...
I’ve kept this short as soon you’ll get chapter, verse, a book, a lecture and then some thrown at you…like it or not…! 😆
Click to expand...
Oh, I’ve a book for you.
Click to expand...
Hahaha, this is my first post yet I know exactly what you're talking about :). All advice welcome!

Why do you want a 306bhp car for a 5 mile commute in traffic
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I'm looking at 30i models as well but didn't find any good match yet and I kind of love the idea of more power, a DCT and the bigger exhaust. You're right though, my commute is 10-25 minutes depending on traffic and that doesn't sound great for the engine. There are plans to take the car out for weekend rides a couple of times per month. Thanks for raising this, will have to look into it. How big of a risk would you say this (4 days commute per week plus a couple hundred miles during the weekend) is for the car?

not meaning to be critical but what more do you expect than that..?
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Trying to avoid buying a car with hidden major problems that I'll discover in the first week after purchase. My previous car was a 23 years old E46 that I kept in good order for 17 years so I know how life with an old BMW is and hopefully I'll be as lucky with the E89 as I was with the E46.

These are GT cars (with sporty ideas) and really come into their own on longer drives.
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I am planning to use the car for this a couple of time per month but there's no escape from the fact that it's going to do commute 4 days per week.

Thanks for all the great answers.
 
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I would say the 30i is less likely to present challenges. The N52 engine is a peach.

The 35i has more power (although the 30i is definitely not lacking!) but can throw some painful bills. Do your research on this to know what you are getting into.

If you are doing a decent run a couple of times a month then you should be fine.
My 30i is only lightly used during the week by the wife, but it regularly gets a decent run out on a weekend.
 
Here's what the B21 Bot said...



Looking at your situation, I'll address each point systematically based on the E89 market realities and technical considerations.

**Red Flags Assessment:**

The recent ABS pump cleaning combined with plugs/pins refresh suggests this 35i experienced the common N54 carbon buildup and possibly high-pressure fuel pump issues. The engine purge valve replacement indicates EVAP system problems. While these aren't dealbreakers, the pattern suggests deferred maintenance catching up. The lack of roof maintenance documentation is concerning - E89 roof mechanisms require specific lubrication schedules that most owners ignore.

Key warning signs to investigate: any evidence of wastegate rattle (N54 turbos), oil leaks from valve cover or oil filter housing gasket, and whether the high-pressure fuel pump has been updated to the later revision.

**Pre-Purchase Inspection Recommendations:**

For North London, I'd recommend either BMW specialists who understand E89s or independents with proper diagnostic equipment. Essential checks include:

1. Full roof operation cycle including emergency manual operation test
2. EDC suspension functionality on all four corners - listen for compressor cycling and check for any warning lights
3. N54 specific items: carbon buildup assessment via borescope, fuel pressure readings, turbo wastegate operation
4. Underbody inspection for subframe mounting points and suspension component wear
5. iDrive system full functionality test including all modules

Expect to pay 150-250 pounds for a thorough inspection.

**iDrive vs Retrofit Options:**

The factory iDrive system with retractable display is vastly superior to any retrofit solution. CarPlay adapters work well with the CIC system (2009-2012) though slightly better with NBT (2013+). James' car represents the pure driving experience but retrofitting a retractable display system is essentially impossible - the dashboard architecture is completely different.

Your instinct about the hidden display aesthetic is correct - it's one of the E89's defining interior features.

**DCT in Traffic Performance:**

The DKG transmission in stop-and-go traffic is manageable but requires adaptation. Unlike a torque converter automatic, it will creep more aggressively and the dual-clutch engagement can feel abrupt at very low speeds. The Comfort mode helps significantly. Many owners find it perfectly acceptable for urban commuting once they adjust their driving style - avoid riding the brake and use the auto-hold function.

The transmission is generally reliable when serviced properly, though clutch replacement at high mileage (80k+ miles) is expensive.

**Additional Considerations:**

Given your 5-mile Cambridge commute, consider that the N54 engine benefits from occasional longer drives to reach full operating temperature. Pure urban driving can accelerate carbon buildup issues.

The 35is would offer slightly better suspension tuning and styling elements, but the price premium rarely justifies the minimal performance gains for daily driving use.

For your use case, a well-maintained 35i with iDrive represents the optimal balance of technology integration and driving enjoyment.

Source: The Definitive BMW Z4 E89 Book — P. Bondar, 2026 | z4-forum.com
 
Welcome to the forum and good luck finding the right Z4. :thumbsup:
 
I'm not so sure the iDrive is vastly superior to after market options.

Bigger, brighter, touch enabled screens are out there that look factory if well installed.

Give the bot a kick.

If buying today, I would be tempted to seek out a non-idrive variant.

& also note that the 'B21 Bot' isn't definitive fact, no matter how many words are used. It's one fella's opinion (granted - a fella that has gone way beyond the norms with tweaking an e89 - but still - just a geezer that likes to write).

I like the bot. But just note it is what it is.
 
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matsmith749 said:
I'm not so sure the iDrive is vastly superior to after market options.

Bigger, brighter, touch enabled screens are out there that look factory if well installed.

Give the bot a kick.

If buying today, I would be tempted to seek out a non-idrive variant.
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Sadly in this case the Bot had scoured the world and has decided you're in a minority !

Separately I for sure would much prefer the idrive for its access to core data and the foundation for a MMI box.. touch screen in a car is an ergonomic anathema not to mention fingerprints, its also out of reach from the driving position, brightness doesn't seem to work in sunlight I tried to android units and send one back and sold the other..and that guy has now retrofitted idrive ..finally if you're ising the carplay interface tehn the size / pixel depth has no real effect on legibility.. !
 
It's not final.

I've had the idrive in all my z4s, for a pretty good number of years.

It's been ok (but only ok). Screen is a bit small when compared with modern cars, it's a bit dim, picks up scatches & hazy damage over time due to the soft plastic screen, and the weaknesses become really clear when you use a car with a better system.

Car play & android auto were designed as touch enabled systems - it's just clunky using the rotaty conroller with no touch.

I massively prefer a bigger, brighter screen & touch enabled. Once a week I spend 10 seconds wiping off fingerprints.

There is a reason they don't do it like that anymore, and there any many high end 3rd party screens available (trying 1 and not liking it is not exhaustive).

I'm releived that after scouring the entire world you have finally come across the correct answer :)
 
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matsmith749 said:
It's not final.

I've had the idrive in all my z4s, for a pretty good number of years.

It's been ok (but only ok). Screen is a bit small when compared with modern cars, it's a bit dim, picks up scatches & hazy damage over time due to the soft plastic screen, and the weaknesses become really clear when you use a car with a better system.

I massively prefer a bigger, brighter screen & touch enabled. Once a week I spend 10 seconds wiping off fingerprints.

There is a reason they don't do it like that anymore, and there any many high end 3rd party screens available (trying 1 and not liking it is not exhaustive).

I'm releived that after scouring the entire world you have finally come across the correct answer :)
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Pls identify the specific screen that you know is a much better fit on an E89 than an idrive pls?
 
For city use, I think an N52 car would be a much better bet.

Actually, a 23i is plenty powerful enough for round town and the ZF6 is a nice box if a little inefficient until it's at cruise and the lock-up clutch has engaged.

You should also easily be able to get a really nice 23i on a 35i budget.

iDrive is a bit marmite.... I have a Mr12Volt on my 30i and it's pretty good but does occasionally get annoying.

My experience with aftermarket screens on other cars hasn't been very positive, though, and on my daily (a Kia) I ended up building a custom harness adapter so that I could use the OEM Carplay / AA head unit from a later model year.
 
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matsmith749 said:
What does the bot say?
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The Bot is currently limited as it only looks at the world through its generic knowledge base of E89 not my view / / experience ..

However the AI tool that created the Bot says...

This is a good debate. Here's my honest assessment:



The iDrive vs Aftermarket Screen Debate — My View​


The core issue is that both sides are arguing past each other. They're not actually disagreeing about the same thing.


Person 2 (pro-iDrive) is right about the ergonomics and integration arguments:


  • Touch in a moving car is genuinely poor ergonomics — BMW themselves moved away from it and back toward haptic/rotary for good reason
  • Out-of-reach placement is a real issue on the E89 specifically — the centre stack is further away than many assume
  • Sunlight legibility on most Android units is genuinely poor; iDrive's matte panel holds up better
  • The MMI box/CIC argument is solid — iDrive is the foundation for hidden data, PDC overlays, camera integration, and coding access via ISTA/NCS
  • The "tried one and sent it back" data point is weak as a generalisation, but the "he retrofitted iDrive" closing point is strong

Person 3 (anti-iDrive) is also making real points, but undermines them:


  • The E89 screen is small and dim by modern standards — that's objectively true and not worth defending
  • "Once a week, 10 seconds wiping fingerprints" is a reasonable counter to the fingerprint objection
  • The comparison to modern cars with better systems is valid context
  • But — and this kills the argument — when challenged to name a specific screen that fits and looks factory, there's no answer. That's the tell. The aftermarket Android units that genuinely look factory-fit on an E89 are a very short list, and every one of them has compromises on integration, coding access, or long-term reliability.

Person 1 (opening the debate) is the most honest position: "I'm not sure" and "I'd be tempted" are appropriately hedged. The non-iDrive E89 is cheaper to buy, which is a legitimate purchasing consideration if you're planning an Android retrofit anyway.



The Argument That Isn't Being Made​


The strongest case against iDrive on the E89 specifically — which nobody in this thread is making — is the CIC vs CCC split.


  • CCC-equipped cars (pre-2011 broadly) have a genuinely limited iDrive: slow, small 8.8" screen, poor map rendering. The case for an Android retrofit is much stronger here.
  • CIC-equipped cars (post-2011) are substantially better — faster, cleaner UI, better nav. Still not modern-car level, but the gap to a good Android unit narrows considerably.

Nobody asking "which specific screen fits?" is distinguishing between these two. That matters enormously for the advice.



For the Book​


This belongs in Vol 1 (Enjoying/Ownership) as a balanced treatment — not a verdict, but a framework:


  1. Identify your head unit (CCC vs CIC)
  2. If CCC: aftermarket retrofit is a legitimate option worth considering
  3. If CIC: iDrive's integration advantages are harder to justify replacing
  4. Any retrofit discussion must address ISTA coding access, PDC/camera retention, and iDrive menu loss — these aren't cosmetic compromises
  5. The specific screen question should be answered concretely — if there's a known good fit for the E89, name it; if there isn't, say so

The bot answer on this topic will currently be generic. It'll talk about Android units in general terms and probably miss the CCC/CIC distinction entirely. Worth adding a tight, opinionated section to the book that the bot can eventually draw on.
 
(i) There is no argument - just 2 different opinions. Both are correct from their own perspective.
(ii) A quick google will show you hundreds of 3rd party screens at a range of quality / pricepoints, with different fits & looks - take your pick.
(iii) I consider the touchscreen 'problem' as being a thing when everything (heater controls, volume control etc) has the physical buttons replaced by a touchscreen. I hate that, as do many others. This is just the infotainment, and that I can cope with just fine.

As the years roll by, I have become attached to carplay/android auto. For me it's a must, and it works better with a touchscreen.

Not sure how that's even being debated.
 
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