BBS CH's are nice, but aren't they kind of heavy?
Other than cosmetic reasons, a replacement wheel should also save you a little weight. Have you visited the Tire and Wheel forum here? There is a group buy coming up on some MORR VS8 wheels that looks pretty interesting. 19' forged wheels which save around 6lbs (maybe?) per wheel? Less unsprung weight is a good thing, btw. $2500 for 4 I think is what the GB is going to go for; they kind of look like the CSL wheel.
I'm thinking about it, and plan on reusing my stock tires, selling the wheels on Ebay or Craigs, or heck, here. Not sure how much I could get for them though.
http://www.m3post.com/forums/showthread.php?t=128661