Would this sound right? on my car i have cat back exuast 3 1/4 inch.. with pod filter and heat shiled..all stock and im getting about .5 bar and then at 5000 rpm it boosts to .7 bar.. so from about 7.4 psi it goes up to about 10 psi at 5000.. is that normal for r33 gtst.. its a 05 model with series 2 engine..