I'm runnin the SR40 at 22-23psi it spools great and good power but I really don't recommend the APS turbos. I would either FP turbos the green is super for me the red would be a little much, it is better on the 2.5L. I ve heard mixed opinions on the GT35R some people have said that the boxer engine spools it better than the inlines (4G63s and SR20s) do, if that is the case it would be my choice.
Good luck with the build
__________________
'02 Subaru WRX 2.5L, SR40 turbo, MRT TMIC, RA gears, ACT clutch & flywheel
'06 Chevy Cobalt SS GM Stg 2 G85 lsd
'94 Acura Integra GSR sold
'99 Isuzu Rodeo 4x4 2" lift, Procomp 9000 shocks, 20" Procomp Knight Khrome wheels sold
'92 Acura Integra RS sold
'04 CRF450R '86 TRX250R