In regards to 17x9 rim, you should be okay with a 255 - depends on what brand you get and also what size wheel they recommend for that tire. Personally, I stay with the OEM SS rim size for the fronts and get a 275/45/R17 tire since that's the stock size on your SS, and won't pose any issues. As for the 18x10.5 you may need to do the BFH mod to ensure no rubbing between the body and the tire - checkout the Wheels & Tires section for more info.
Do you do any suspension mods as these will also factor in to whether or not your planned wheel & tire upgrade will work or any more work that is needed to make them fit right?
Last edited by Switchblade; Apr 27, 2007 at 08:16 PM.