Welcome Ozzie. A lot of guys are running 15x8x4.5. 4.75 bs would be better but it's going to depend on the tire size and just how low you go. What tire size are you considering? Hopefully Don (dhutton) will drop by and give his input. He's normally spot on.

 

Welcome, There quite a few wheel and tire threads on here. Post up pictures of you ride.

 

Were you able to lower your car and choose new tires for it? I had my suspension checked for damages and calibrated adjustments. There won't be any sizing problem as told by my mechanic when I showed him the set of Nitto tires that I want to install. Hopefully, you're able to execute the modification without much problem.

 

You can go bigger than 15x8. The Crusher Camaro has 18x8 with 5.25” bs for a while with 275 40s on it. It’s is mini tubed but he commented having seen that combo used with success with stock tubs.