^^ further to this, make sure you get the dump and front pipe done. A lot more important than just a tailpipe.
There are a couple of dump pipes, Scotty makes one and AM Performance do a good one too.
Most important thing to do is get rid of the restrictive dump and box if baffles in the mid pipe.
Don't go to your local exhaust shop and get something made up unless they've done other M35s or you'll end up with something too loud.