[F1wheels]

I wanted to ask if any of you guys experienced problems with just aftermarket bolt-ons? I have the Dinan 2 core IC, Dinan CAI, Berger Mtrsprt Charge-pipe,VRSF catted down-pipe and VF's Stage II Tune.
My car runs great up until about 6k rpms then it will stumble and sputter. I have already replaced the coil packs as I had a Fault Code indicating that one was bad, but that did not solve the problem.
It will almost seem to clear itself out if I keep my foot in it. But my AFR gauge is reading very lean at that point so I figure that the factory pump cannot supply enough fuel at the high-end of the rpm range. If I decide not to go to a Pure Turbo Stage II set-up any recommendations as to whether I should replace the lpfp in the tank or should I spend the money on either the XDI or go with the Port-injection set-up from Elite Fueling Solutions?? What I don't like about the Elite is the entire intake assembly has to be removed to install their manifold spacer with the built in fuel rail. I feel the XDI system is much simpler to install and they send you the flash file for the pump configuration.
Thanks,
David