What are good aftermarket parts for my BMW 650i?

I've been looking for aftermarket performance for my BMW 650i and so far Dinan offers the most products but I think they are way overpriced for the hp gains. Any companies you car enthusiasts know of for the BMW 650i?What are good aftermarket parts for my BMW 650i?The good thing about Dinan is that it will not affect your factory warranty and from all I've read they will stand behind the products. Downside is they are quite pricey. Turner motorsports probably has some stuff. Also try Alpina, Hartge, AC Schnitzer, Hamann though those will primarily be appearance related. In the US check bmp design, bavarian autosport, maybe find an e63/e64 forum and ask them?