Yeah that's the safe limit imo, im going exactly the same, 15psi and 6750 soft 6800 hard rev limit. I'm gonna get a grp A filter, FRS TB, FRS rail (going to ask if he will chuck in sensors) for £90 What do you think?

Also seeing as everyone has been so helpful so far.. One more question, theres a 12000 mile std cat back FRS exhaust system come up. I want it but is it good for 300bhp mark?