Depends on how far out you need to send the wheels. Any amount will put more stress on the assembly. Can also use longer bolts to ensure a safe fit with the lug nuts or use spacers that have new bolts on them if you're going extreme.

Went with Steve from RPM to a small corner shop out by Richmond Dragway that had wheel spacers in stock. Wish I could remember the name to pass along. The bling-bling shops on West Broad should have them as well.