Re-build
What I have done to my P5 today is completely rebuilt the whole engine I had the engine over heat, blow a head gasket, and causing my head to warp did a whole bunch of stuff that was bad. But me and another fellow import tuner, rebuilt the whole motor. New bearing (mains & rod...
I took off one my cats that I had on my P5, and I also have megan cat-back exhaust.
Later, with more dough... OBX headers, Injen Cold Air Intake, Turbo kit upgrade.