Having worked for and on BMW's for 11 years the E36 is the only M3 i wouldnt buy. The E46 is a better car full stop, not only in quality but also the way it drives, handles, performs, the engine is relatively bullet proof, buy a coupe in a manual and your not going to have many issues.
Convertible are nowhere near as good as the coupes and that goes for E36 and E46 models