I have a Spec suspension on my 1988 944 and is really low. I run track events with 15x7 23.3mm Cookie Cutter wheels with 225/50/15 Toyo RA1 tires and they do not rub at all. I have about negative 2.5 camber front and negative 2 for the rear.

This setup will bring the wheels and tires almost flush with the fenders and looks awesome. Make sure you use the Cookies for the race track as they are about 2.3 lbs lighter per wheel which is a big advantage for racing/track.