I never did a spread sheet… Its costs what it costs no point in worrying about it IMO.
Bearings, vanos, and engine mounts - I would not be concerned with. Generally the cars that have had problems are cars that have been used more spiritedly or on track where 20k is more like 100k wear. But it should also not be forgotten, as the car gets to 80k+ I would have the bearings and engine mounts replaced under regular maintenance. Having it all done at once shouldn't cost more than £1200 also I would have the vanos checked but it is covered under your inspections anyway. The bearings were altered in the S54 before the Z4M was produced so in theory all Z4Ms should have the updated bearings therefore more reliable, think the specification of oil was changed too but can't remember off the top of my head.
If your worried about engine mounts, I have had mine looked at recently and if you know what your looking for then its an easy check, get a torch and you can see them in the engine bay. if there are issues, the rubber will be showing signs that it is perished on the outside thats your first clue. People say because the right hand side mount is so close to the engine it suffers from heat soak and fails but it is so heavily shielded I don't think its as big of an issue, the right side is the one that fails (right side as if you were sitting in the drivers seat, left if looking into the engine bay) second clue is that the engine will start making a clanging noise as the engine will have moved slightly probably hitting the strut which is much more serious, could have gearbox issues also. But thats worst case scenario and only one person in my memory has had this.
Other problems, top mounts can go more so on the rear apparently. These will give you a squeaking noise, springs are rubbish a lot snap so worth a look, fairly obvious it will creak won't handle correctly and also one side of the car will look lower. Gear box is notchy between 1-2nd this is because it is a getrag gearbox with a clutch delay valve like all manual M cars non issue for me you get used to it very quick. There is a problem of acceleration delay don't know much about this because my car hasn't had an issue but there is an epic thread somewhere. Interiors seem to wear well but some components aren't brilliant, steering wheel surrounds the multifunction buttons these peel, bolster on the drivers side is prone to wear because of how low the car is, cigarette lighter door is a bit flimsy. Paintwork… because they are very low the front usually gets well peppered as well as the front and rear of the skirts, also in and out of the drivers side banging shoes on sills etc all easy to sort cosmetic issues.
Most important thing is service history, ensure the 1200mile service, if not walk simple as that. Make sure the car has had an oil service every two years or 14k if it hasn't again I would move on, not worth the hassle and BMW will be less likely to give good will if service history is late or missing. Make sure it is FBMWSH otherwise you won't be able to get a fully insured BMW warranty.
But the worst case is worth knowing so you can evaluate a car your looking at.
Like any high revving sports car, tolerances are tight and ensuring the car warms, oil up to temp etc before exceeding 3k revs is paramount at all times.
Again these are very rare occurrences off the top of my head since I've been on the forum not one M car has suffered any vanos issues, only one has suffered bearing failure and two have had their engine mounts replaced. Its something to bear in mind and have money to do in your maintenance schedule.
But I would stress, because you don't know how your car may have been treated in the past. Buy a warranty, that £85 a month may save a £10k engine replacement if the worst should happen. Even just small things my window was pissing about after I had the key reprogrammed, in the end they changed the window motor and the ECU and reprogrammed it which was £1500 in parts and labour, my xenon went, control unit and labour £780, had a sticky calliper parts and labour £500. Although these cars are good value to buy the parts are expensive so the warranty in my mind is a must. It has paid for itself 2 fold in the 2 years I've owned the car and my issues have been fairly minor.
NON of the above would put me off what so ever. There have been far more issues with the 3.0l variants than the Ms.
Like said there are many E46 M3s hitting 150k-200k still without an issue apart from what I would consider standard wear replacement items which the above would come under.
The S54 is a cracking engine and very reliable for the type and performance you get. But you also have to be a bit of a geek to keep it running smoothly. But all is documented in depth across this most brilliant of forums.
