I have a B&B Tri-Flow exhaust on my 87 535iS, and I think it sounds good. It is pretty damn loud and I set of at least one car alarm everytime I drive the car....but I still love it. I made a video of my car and it shows what the exhaust sounds like.....check it out on my cardomain page, it is the link at the top that says "the first of many videos....."
<img src='http://home.comcast.net/~evanswink/bremerton-9.JPG' border='0' alt='user posted image' />
1987 BMW 535iS
BBS RS with Yoko AVS ES100
BavAuto lowering springs/ Koni Yellows
B&B Tri-Flow exhaust
MOMO, Alpina, Factory ///Motorsports, Alpine, JBL, JL audio goodies on the interior.
TONS of cash everywhere HA!
<a href='http://www.cardomain.com/id/fastfiver' target='_blank'>Check out my ride on Cardomain!</a>
"I don't drive fast, I fly low!"