[Paul Huryk]

You can fit a 275 in front and a 315 in back with the right wheels pretty easily. Problem is that 315-35-17 tire selection is not good - only about 5 tires that comes in both 275 and 315 sizes to match.

I have seen a few cars with 315 all around - either in 17" or 18", but you will have to make some modifications and sacrifices to do that. The result is an ungodly amount of front end turn in and at the limit traction with the 315s on all 4 corners. Going from a 275 to a 315 all around is about the same increase in grip of going from a 245 to a 275, which is a big improvement.

One thing to realize is that front heavy cars like the f-bodies handle best with a square tire setup (same size in all 4 corners), which limits oversteer and increases mechanical grip. So either 275 (easy) or 315 in all 4 corners.

As Tim mentioned, there can be a huge increase in grip from going from a 275 all season tire to a top of the line summer tire, sometimes approaching 10%!