I built a vr6 turbo with a 3076 in 2006 it did 422whp at awesome gti dyno !
I broke 4 third gears in 5 thousand miles so I think I can safely say I know what I'm talking about .
If 11psi is your goal and 300ish bhp is all you want then a 30 is fine but over 400hp you are really starting to work that turbine .
Its exhaust manifold pressure that's the problem with a vr6 turbo !
I spend half of my life at a dyno and my friend maps one of the most powerful vr6's "r30" in the country , im not just going off what someone has told me I have been there a long time ago !