I'm putting 997 turbo wheels on my 996. I have the factory shocks with H&R springs. This did not clear the spring perch at 25.8" diameter. With a 7MM front spacer it clears and doesn't rub anywhere. A 15MM front spacer provided much greater lower perch clearance and the wheel is flush to the fender but made it rub on the front radiator bump and the front back lower fender area.

I've seen some posts of 245/35R19's just bolting on but I see otherwise so FYI.

 

could be difference in sidewall dimensions brand to brand.

 

Maybe the Pilot Super Sports run wider then normal.

 

PSS's have a very square sidewall and can fit a lot tighter compared to the same size pirelli for example due to the different designs of the sidewalls.