Well, after months of consternation and haranguing, and asking people's opinions (both here, my mechanic, and other sources), I finally decided to do some Dinan to my E39 and have their performance muffler installed. It's a cat-back, so the rest of the exhaust is stock. Here's my take on the results of the decision: Sound - wow...it's everything I thought/hoped it would be and nothing more, which is what I wanted in the first place. We've all seen the cars with the after-market mufflers installed and frankly they are a sound nuisance. This is not like that...throatier, fuller sounding without overtaking, it sounds like a BMW sport sedan should IMO, especially in 1st and 2nd gears. Performance - Dinan's website speaks of a modest horsepower boost, nothing special, and my mechanic confirmed this...I do notice a bit of a boost. But more importantly, and crazy as it sounds, a louder exhaust actually improves my shifting! Now that I hear the car, I'm better at the timing. Look - well, check out the attached pics and judge for yourselves. I'm happy with the look but not jumping for joy; it's clear this car was designed for one to not notice the exhaust pipes and if I were king of the world I would want it to sit a bit higher. Final Grade: A-...the bottom line is, I'm able to enjoy the car even more with this installation and that's what it's all about!