Hey guys. I'm brand new to the forum, and just throught I'd add an exhaust to the list: Scorpion STW for the 325i.
Bavarian Autosport (yeah, I know they'er overpriced, but...) has the Scorpion cat-back exhaust on clearnace right now for $550+s/h. Full stainless steel cat back. That price is hard to pass up.
There aren't any videos (that I've seen) for the E90 3.0L engine, so I'll be posting install pics and an HD video of sound. I may even borrow a G-meter to measure actual power increase before and after.
We shall see...