I did some comparing, the stock 2.0L 911 T with 8.6-1 and a 2.0L 911 S with 9.8-1 compression. Knowing the valves true closing point, and the static compression ratio, I can predict the effective compression both engines will see. Of course the T engine will have less "VE" than the S engine. But this is interesting. The T running compression is 7.3-1 and the S is 7.5-1 even though the S has 1.2 more static compression.