I do know of only one person who makes a header upgrade for the 3.6L gxp and that is MMS, which is ridiculously priced at 900+, but does anyone know about any throttle body upgrades? I have a friend that is going to carve out some cams for me if i just give him my cams for a few weeks, so i am looking forward to that. I am also about to cut my own throttle body spacer considering the one that poweraid makes it not worth the price at all. The spacer is like, 1/8 of an inch??