Hi Rob
I have owned 11 e36 M3s not a lot goes wrong
Vanos is an issue with them you can tell let the car tick over open the bonnet and give it a rev when the revs drop you will here a rattel slowing down if it does the vanos or the vanos gears are on there way out.
I liked the 3.2 evo over the 3.0 better car to drive and better on fuel
rear trailing arm bushes go on them if they feel lose at the rear
also top shock mounts are crap £21 each not a big problem.
black leather is the best as the silver leather does not wear well
I had 1 convertabile but its not me would not buy another
There are some great e36s out there but there is also a lot of dogs
This was my fav e36 M3 Ac Schnitzer only 3 in the UK