I run the PPE boost valve and hit 32psi. And I wouldnt go much higher. If your running enough fuel to hit that much boost the turbo is likely to bark if you get out of it too fast and over time this is not good.
The most I could ever hit with the edge on 5 when it was on my truck for some experimental stuff was 28psi.
I run 4-6 while cruising at 70mph down a flat road, but thats with 35s too so the RPMs are lower,
and just daily driving with a slightly large tune in I never see over 20psi unless I really get on it then I can peg 33psi, but I find that I rarely do this as my tired tranny slips.
All of my readings are from an autometer 35psi boost gauge.