Turbo Question Big Enough?

[galoush]

Hi everyone , i have on my Car a Jack Cotton CPT65BB with 63 housing . The car has ported GN1 heads along with a Tony Dequick sheet alum intake . I was out yesterday and tried to crank the boost past 20 psi but it just wouldnt go higher . Now im guessing the heads and intake is outflowing this turbo what do you guys think , i ran 30 psi with this turbo and stock heads and intake . Whats a good turbo for this combo with out getting too ridiculous for street driving too .Thanks