It's the weak point in all these cars, especially the GXP.
Been there; done that.
You'll be dumping nearly the cost of a turbo kit or whatever power adder you choose into the transmission just to be able to handle the power. To save it now; hopefully...do a pan drop, shift kit, new filter, and a trans cooler. Bypass the radiator as well.
For a power adder..either heads/cam/nitrous...or a turbo kit. Either will put up about the same numbers. Both will cost probably about the same in the long run as well.
