Well, I have the stock IP maxxed. I can blackout an intersection when at low rpm if i am not paying attention to my foot. I would max your IP and see how much is unneeded and back it off from there. The boost wasnt as high as it is now when i was running 2 full tuens on the IP. I went back in and got another 2 turns out of it before it was maxxed. I am also running 4 dimes worth of advance on the IP, I have no idea what that actually ends up being as far as advance especially since the IP has 152k on it.
What is the model number for the turbo on your system?