Well, I know for sure that P2s are massively faster than GT500s on high speed corners like Coca-Cola and 100R and, as Suzuka has shorter straights and faster corners, that would favour P2s a lot.
I already posted this before, SGTs are much closer to SFs on Fuji than on Suzuka. Best time SGT ever did on Suzuka was 1.47.6 while SF's best was 1.36.9. On Fuji, SGT's best is 1.27.5 and SF's is 1.22.5.
5s gap on Fuji(6% more) and 10.5s on Suzuka(11% more)
Additionally, if we assume P1-Hs would lap around the same as SF on Suzuka, then, applying Silverstone percentage(from P1-Hs to P2s) we could predict a P2 laptime of ~1.45.3 on Suzuka.
This is just some very rough extrapolation, obviously, but I just did it to show that my claim is not far-fetched
