I am running a 21st Century sub so no spacers were required. They bolted right up. The rear has about 1.5 inches of tub on each side and the rearend was built to width, so no spacers on the back either.
I think Jake's front sub and AME both take a stock offsett Corvette wheel but I am not positive. Give them a call.
Lot of questions on the C6 and C6Z06 rims and tires. They are a nice looking and strong rims that are really cheap. I paid premium dollar for mine because they had just come out in 2006 when I got a set. Check out
www.corvetteforum.com in the for sale section....lots of deals.