C6 20x10.5 in the rear and 18x9.5 in the front?

I was thinking about getting these C6 rims http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=260002966049&sspagename=ADME%3AB%3AAAQ%3AUS%3A1 for my 99 Camaro my question is how do you think they would look with 18's in the front and 20's in the back? Right now I have 20" zinik adrains all around and want something new and have a question about them to, my brother has a 98 Linclon Continental and I want to sell him my rims with a
5x120.65 lug patern but his cars lug patern is 5x108 is there and adapters or something I can get or do to make them fit his car?
You can see the rims I have now here http://www.1010tires.com/wheel.asp?wheelbrand=Zinik&wheelmodel=Z7+Adrian&pc=Z07%2D20%2D845C4273 if anyone is intersted in buying them let me know and ill give you a price and take some pics.

Im not a fan of stagered wheels because of the mis matched sidewall height. It only looks good if the car is made to have larger diameter wheels in the back to keep the sidewall height the same but have the larger rims. 20"s are too big for my taste but if you must then have them the same all round, or go wider in the rear.

Yeah im not really sure what they would like with a two inch diffrence. What do you think about for the front tires 255/35/18 and 255/35/20 in the rear so the sidewall would be the same size and then just lower the front about 1.5 inches to close up the wheel well gap?

Skulte could probably make you adapters for the 5x120.65 -> 5x108 conversion.

http://www.skulte.com/

Its gonna look like a Prowler.

I decided to go with 19" in the rear and 18" in the front. And thanks for the link I emailed them about the adapters and they want $155.00 per pair, that was a little more than I was thinking but ill just look around.