Hi Zoid. So you're supercharging your Z4 eh ? Great ! Welcome to the club !
Apologies for my delay in replying to your original post but as has been previously mentioned I was part of Lewis Jennings group buy of Infinitas (G-Power) superchargers back at the end of 2021. I fitted the kit myself in February/March last year followed in April by a 'shakedown' weekend with some forum friends in N.Wales and then a 1,400 mile round trip doing the NC500 in Scotland. The car has now done almost 5,500 supercharged miles in total...without a single fault or issue
So, a little background to my install. I was in the motor trade for 30 years, 15 of those with the Halliwell Jones BMW Group. I instantly fell in love with the Z4 on its release in March '03, particularly the 3.0i E85 demo with SMG gearbox. A change of circumstances and career in 2014 and I wanted to acquire a long term project car to 'keep my hand in' as it were. I looked high and low for a nice 3.0i E85 with SMG. Eventually in Jan '15 I found an immaculate, 2 owner, low miles (53k), well spec'd example...with a hardtop too, for £3,900. However, it was a 2.5i. Oh well, Hey-ho ! I can live with that. You can't have everything, right ? In the 8 years since then I have changed/repaired/replaced/'upgraded' almost every component, acquainted myself with every nut and bolt and slowly fallen in love with the car...but all the time wishing it had maybe just a little more power, a bit more torque...more oomph !
So when Lewis announced on the forum that he had negotiated with Infinitas for superchargers at exceptional prices it didn't take long for me to put my name on the list. So I would be getting an increase of about 60 hp and 45 Nm, a challenging project and self-satisfaction all for the princely sum of £2,245 inc.shipping, vat and import taxes/duties.
The kit itself is robust, simple and reliable with no charge-cooler required. Lubrication and cooling is via an adaptor into the oil filter housing and draining back into the sump via another adaptor on the dipstick tube. Nice and simple. The s/c can easily be fitted in a couple of days by any competent mechanic, although my Z4 was up on axle stands for 6 weeks as I also took the opportunity to overhaul/clean/paint quite a few other components at the same time, working in the evenings and weekends. As I'm not massively computer savvy the most worrying part of the install for me was the map update via my laptop and the supplied OBD cable and I-Flash download. It was actually surprisingly easy
Anyway, the car is now just shy of 250hp and torque is up to 290Nm which is a huge transformation and in conjunction with the SMG makes for a superb drive. Just right, not a surfeit of power but enough and the increased mid-range torque makes things much more entertaining and satisfying...especially when you've done it all yourself
IF you feel like you do require more power then there is always the option of a smaller s/c pulley and different map

M-Style have this same Infinitas kit on their website at £5,500

https://www.mstyle.co.uk/bmw-z-series/z4-and-z4m-e85-e86/tuning/superchargers/g-power/g-power-sk-plus-rs-supercharger-245-for-e85-e86-z4-2-5i.html
From a German seller on Ebay it is approx £3000 + £170 shipping from Germany, which I think is still superb value for money especially when you sound like you intend to keep the car a long time... like I do. Mine's a keeper, I have no intention of selling it. Having said that somebody did make me a very serious offer for the car last year but upon reflection I love the car so much, enjoy it so much, have invested so much of myself in the car over the years that I just cannot part with it. I would regret it for a VERY long time
Zoid, I'm up in West Lancashire so I'm afraid I can't recommend any tuners down in the South West to do an install but I can thoroughly recommend the Infinitas Supercharger
A few photos of the supercharger kit, stages of the install, finished product etc.... to whet your appetite









