Yes 2007, 997 TT

 

I run the below without issue.

Summer 20's - 245/30 & 325/25 mpss
Winter 19's - 235/35 & 295/30 dunlop d3
Track 18's - 255/35 & 335/30 r888. I plan to try 245/40 & 305/35 nt01 this season.

All of the above are very close to stock front/rear diameter (or circumference) ratio.

 

I have the same size winters.
my 20" summers which are being made as we speak the tires I got for them are :235/30/20 and 325/25/20. The difference in tire height is like 2mm vs stock. Cant imagine the computer is that "finicky".

Guess we shall see, I think there is a lot of misconceptions online and in people's opinions of what you can and cannot run in terms of tire sizes.

Real life experiences is what matters most.