The short version
- Ask whether the crank hub has been done. If not, budget for it.
- Check the history: oil changes, who's done the work, and whether it's been remapped.
- Look for blue smoke on start-up, warning lights and signs of hard track use.
- Once it's yours, our £149 post-purchase inspection tells you exactly what you've got.
The F80 M3, F82 and F83 M4 and the M2 Competition are some of the best used performance cars you can buy right now. They all share the S55 twin-turbo straight-six, which means they also share the same handful of things to check. Here's what we'd look for.
Which one would we buy?
We like the M3. It wears the flagship badge, the rear arches give it real presence on the road, and if you need back doors, it ticks that box as well.
Know which engine you're buying
The F80 M3, F8x M4, M2 Competition and M2 CS all have the S55. The original 2016 to 2018 M2 (non-Competition) has the N55, a different engine. It's a great car, but the S55 checks below are for the S55 cars.
1. Has the crank hub been done?
This is the first question to ask. The S55's crank hub isn't positively locked to the crankshaft and can slip with no warning, on tuned and standard cars alike. If it hasn't been done, budget for it: it's from £2,049. If the seller says it's been done, ask for the invoice showing what was fitted and who fitted it.
Read more: S55 crank hub explained.
2. Has it been tuned?
Lots of these cars are remapped. That isn't a bad thing in itself, but you want to know who did it, what was done, and whether the supporting work, crank hub included, was done too. It can be hard to tell a car has been tuned if the seller doesn't say, but it's something we can find out during a post-purchase inspection.
3. The service history
Look for regular oil changes, ideally well inside BMW's maximum interval. We recommend every 5,000 to 7,000 miles depending on use. Look for work carried out by a specialist or main dealer too. Gaps, or long stretches between oil changes, are worth negotiating on.
4. On the test drive
- Start it from cold if you can, and watch the exhaust. A puff of blue smoke on start-up, or after idling, points to valve stem oil seals (from £1,699).
- Listen at cold start for a tap from the front of the engine that fades as it warms up. That points to camshaft alignment (from £999).
- Check for warning lights and ask whether any fault codes have been cleared recently.
- Feel the gearbox. DCT changes should be quick and smooth, and a manual shouldn't crunch.
- Look for signs of hard track use: heavily worn brakes, tyre wear on the shoulders, or worn trim around the seats and wheel.
5. What to budget for
Even a good example may need some of the known S55 jobs. Our S55 common problems guide lists them with prices. At the very least, budget for a fresh service when you buy (from £299) so you know exactly where you're starting from.
Once it's yours, get it checked properly
Our post-purchase inspection is the easiest way to know exactly what you've bought. For £149 including VAT, we inspect the whole car from top to bottom, including diagnostics, and give you a full report, so you can plan any work and budget for it properly.
