have u considered doing some kind of bottom end work to the motor in the event that he does want to turn the boost up??? i mean if he has the money and you knowing him have a good idea on the type of guy he is ( being happy with 5psi or wanting more power) may want to recommend that option to him.

I just personally dont see the point of doing twin turbos for on 5psi. now i know that he just wants to say he has it, but like i said to a guy like me it doesnt make sense.

goodluck and listen to what the people have said here, there is alot of good info.