Well the question of what exhuast should i buy comes up quite a bit, so i thought i would try to clear up some of the confusion. Feel free to ask more questions if you have them, but if you just want to know which is louder etc please refrain from making a new thread.
First of all for all of us non m3 owners you can pick up a used m3 catback system. This exhuast will fit all e36 model cars. I hear the 96+ exhuasts are bigger than the 95 and are a better one to pick up. You can usually find these in classifieds on different bmw forums. Most people as around 150.... Realisticly most people pay 100$ but sellers know they can get up to 200$ from some people so dont be afraid to barter a little.
Now for SOME aftermarket exhuasts (i will update this list as i am sure i will be told i left out X company) so feel free to PM if you noticed i forgot a company.
AA tuning Gen 3
UUC System U
UUC TSE (no longer in production)
Im sure there are a few that i left out, so feel free to PM
list of some and you can listen to them!