Wow, thanks a ton for the info.

I plan on running the 15 inch subzero, 6.5 indes wide. I don't think I will have any fitment issues as people have managed to squeeze much,much larger wheels under the car (19 inches) without problems.

The offset won't be too drastic of a change at all. The guy I did talk to was running Hoosiers with his xA, so that might be why he recommended such a low offset. These will be dual purpose wheels though (street/autocross), so I don't need something that drastic.