Looking at a 2005 M3 with 71,000 miles. Car looks very clean, one owner, it is for sale at the dealer for $21,000. What do I need to look for before I purchase?
It is usually recommended to get a PPI (pre-purchase inspection). It will cost you $100-200 depending where you go, but they should go over the car thoroughly and let you know about any deficiencies, wear, broken parts, etc. A reputable indy shop or a trusted BMW service center can do that. I'd also make sure it has the full maintenance records. I bought a 2003 M3 convertible from an indy dealership. I'm the 3rd owner, and I failed to get a PPI or get the records. I've since learned that while I love the car a lot, I probably should have bought a different one. Luckily I bought an aftermarket warranty with the car which already saved me over $3K. But I've also had to do some reconditioning of the car.
...and if you decide to buy the car, get the buyer to negotiate the pre-purchase inspection off the top.
Don't get the PPI from the dealer selling the car, or have an indy that knows Ms check it out. +1 on the maintenance records, no matter how clean, if it hasn't had the oil changed and valves adjusted, stay away.