You probably all know that the E36 BMW M3 is one of the most engaging rides out there. As a physician and car enthusiast I can only say that if you cannot have fun in this car, I will refer you to one of my psychiatrist friends (after I check to see if you have a pulse though). It's also the most fun you can have with your clothes on unless you drive naked.
But before the fun starts, you have to remember--you have to pay to play.
There are many issues with the E36 bodied M3. I have learned all of these issues the hard way and want to share my knowledge to save a lot of the pain. After all, some of the cars you will be considering are over ten years old. I will outline these issues in general categories.
1. Exterior:
A. Paint--If any car needed 3M clear bra, this was the one. The paint WILL get sandblasted no matter how good it looks from a distance or how slow someone has driven the car. The relatively flat front profile of the car creates a huge area of paint that can easily be chipped. This includes the metal grille surround, front air dam, leading edges of the front fenders, the hood, and the side view mirrors. These will all cost, conservatively speaking about $2K or so to remedy, unless your cousin runs the local Macco. Although everything looks great in pictures, have the seller send you photos of the areas listed above in dark light with FLASH. All the paint defects will pop up magically. Price accordingly.
B. Headlight covers--the headlight assembiles on this series of cars is crap. The plastic lenses, like the paint gets messed up. The plastic gets so foggy that sometimes you have to wonder if the headlights are on at all. The solution to this is to get the European ellipsoid assembiles. They have glass covers that are more resistant to pitting and are replaceable if they get damaged. A xenon (HID) upgrade is highly recommeded as well, although you should make sure to get a kit that is 50W because the 35W kits will make the "low beam light failure" warning come up on the on board computer. This is really annoying, but is a good trade off for proper lighting (especially at really high speeds).
C. Windshield--will also be pitted heavily, especially on older cars.
D. Wheels/tires--watch out for CURB RASH! Unfortunately many M3 owners have more money than brains. They happen to park by feel--feel being the sound of one's rims scraping against the curb. The tires are low profile and lips of the rims are pretty prominent, which leads them to be easily damaged. Refinishing wheels costs about $200 per rim. You can also get them on ebay, but make sure you do not buy fake ones. Check the rear tires--they wear out pretty fast.
E. Collisions--each body panel has a BMW factory sticker with the VIN number on it. If it just says BMW DOT, the panel has been replaced. Ask the seller for these pictures as well.
2. Interior:
A. As far as I know, my major beef is with the Recaro style seats that are found on both the standard M3 and the luxury package. Although they look different, both are especially succeptible to side bolster wear due to the aggresive bolstering which hints at the car's performance potential. All I can say is that it looks really nasty, but is probably par for the course. You can get the seat leather replaced for about $1K. Check the BMW magazines for outfits that do this. This is more of a warning of what to expect than anything else.
B. Glovebox door can sag--not an issue with my car.
C. As with any car, look for nasty spills that have been covered up or are not readily visible (under floor mats, the seats, between the seats, etc.) This is probably out of your control if buying on ebay, but hey you got to be prepared.
D. On rough pavement, interior noise can be quite annoying. There are lots of body rattles and "booms" like the ones you hear on ghetto cars with bad sound systems in even worse cars. Car is nice and tight on smoother pavement however.
...read the full guide with pics here