I just bought a 1994 325i and I've noticed the exaust is very deep and rumbly. A friend and I checked for leaks through the entire system and couldn't find any. We concluded that the sound was in fact comming from the muffler. It is the original stock muffler with about 90,000 miles (and 11 years on it) so I think it probably has just lost a lot of whatever dampens the sound in there.
I need to buy a new muffler but want advice on what to get. I would prefer an OEM stock BMW one because I don't want some aftermarket "performance" muffler/exaust system with some modified note. Aside from going to the dealer how can I find a muffler? Which mufflers will work (whole e36 range?)? Should I buy new from dealer or try and find one used or scraped on eBay? When I search ebay all I find are cheap japanese aftermarket mufflers.