Definitely check the timing, as Perry has noted above if your ignition box is retarding your timing it will kill torque. Next check for vacuum leaks, and make sure the EGR valve is not sticking. The
oil in the boost pressure gauge line sounds like you may have a problem with your PCV valve. Try replacing the PCV valve. Blown motors can build a lot of crank case pressure that can overwhelm the stock PCV system so you may need to investigate improving the crank case vent system.
I recently installed a Pro-M MAS and matched 42lb injectors and I had a bad stumble off idle that was due to air fuel ratio, I tried bumping the fuel pressure but the EECIV will re-learn and correct the fuel mixture up to 20% from the nominal value basically taking out what you just put in.
The way I corrected my driveability issues was to have the car dyno tuned and a custom chip burned. The difference is night and day. So, even if you spent the $$ and bought high quality items that are "matched" you may still have a lean condition. Be careful leaning hard on the motor until you get it figured out, you don't want to burn a valve or worse.