My Big16g boosts around 2600 and full boost (1 bar / 15ish psi) at around 3200. Definately need a new clutch / flywheel. I use 2600, daily use isn't bad at all, and have never had trouble putting down the power. Boost leaks for sure, no way it starts spooling that late. I shift at 3k around town and already have enough boost to blow off, so you should check it out. Check your intercooler piping, a loose hose can cause major leaks. I'm having issues myself currently -_-

EDIT: Forgot to add, I see boost all the way to redline, I think it has something to do with it being ported and clipped, not sure. I am for sure that I get power all the way though, I have tested it enough times

'95 GSX - Big16G ~ Leaks, but atleast it runs.