you need 20x8.5 with a 10mm-14mm offset
and a 5x120.65 lug pattern, not a 5x120 pattern.
alot of wheels on ebay state that they are chevy, but most are not.
if they say both BMW and Chevy in the same ad, they are lying. trying to get a sale out of people who don't know any better.
RVM wheels are not the exact lug pattern for GM