Would you go with 20's on your c63 yes or no?
I am looking at Hre's and Cor rims.

Big mistake, 19's are the best size to go with.
20's are just for show, will hinder overall performance on this car..

Too heavy, big and clunky. Get the factory 19s they are beautiful on this car.

Does the 19's come with the performance package

18" provide better traction in braking and acceleration due to bigger contact patch with the road. It is lighter and better in wet/snow conditions, "softer".
19" provide better cornering
20" provide best looking appearance and raise compassion to a driver

http://www.speedtv.com/forums/viewthread/319031/

I'm getting my HRE C93's in 20's installed in a couple of hours...They just came in finally yesterday after waiting 3 months for them...The Competition Series just came out in 20 inch sizes back in Dec...And from what I've been told, I'm the only person in the US other than Bulletproof's GTR that has 20inch Comp Series HRE wheels. They are very light weight and in 20 inch sizes weight around between only 22-23lbs...Plus since it's a step lip wheel, it's not going to look huge...I'll be posting up a new thread on here with pics hopefully by tonight.

I am sure it will look good. I hope I will be getting my 360forged in 20s really soon too: SL10s in 20s though I think it might look big.

I got 20's it looks great but performance wise you feel like you are driving on metal lol....you sacrifice comfort for style.