2010 18s camaro steel on a 02 extreme
 

1) what size spacers will i need? 2) what are the recommended tire sizes? I was think a 245/45/18.

Not sure on the size (I think it's like 2 or 2.25 inches about), but since you have to get some anyway, get ones that convert from 5x4.75 to 5x120 instead of just a 5x4.75 spacer.