psicks

I have been having boost problems with my stock twins since my AST blew a few weeks ago; I installed a new AST and a Boost Guage after this happended and I noticed an irregular boost pattern at WOT from 3000 rpm to 4500 rpm the car boosts at 0.9 to 1bar and then past 4500 rpm it drops to 0.4 bar and stays there to redline the car idles at 300mm/kg vac. Before this happend the car boosted perfectly (as far as I could tell) and you would get a jolt at 4500 and then strong acceleration all the way to redline however now you get the jolt (sometimes) but the power stays the same as it was upto 4500 rpm.

Let me also add that since the AST blew the car has been leaking a small amount of oil from somewhere on the front right hand side near the turbos, the car also smokes at startup with a thicker blue/grey smoke that burns your eyes and nose I also found a small amout of engine oil in the intake hoses from the intercooler and rad.

The car itself is a stock '92 RHD JDM FD3S with the only mods being the AST and Boost guage I installed myself, car runs on 94 pump gas.

I am really confused because from what I have read this sounds like a Vac hose issue but the oil leak and oil in the intakes suggests that it could be a blown turbo (secondary), I am also concerned that the car is boosting at 1bar with no mods and a stock ECU. Any help narrowing this down so i can actully get to work fixing it would be appreciated.