Hey guys, needing tire recommendations for my dad's GT500. He's running 18x10.5 black chrome FR500's, with a pro kit and the rear fenders rolled and no other suspension mods. I was thinking a 305 or a 315 tire out back. Would either tire work without any other modifications? We've decided on a drag radial for choice of tire, more than likely the 555r but open to other suggestions. Car is a weekend only, nice day type of car.