getting the uppipe is a nice upgrade just because u got a catalitic on it before the turbo(im not sure if the 07 has it too) by eliminating it u let the turbo spool a bit faster and prevent from damaging the turbo too if the cat fails. but taking all the cats out and going straight all the way back works great w the Tdo4. i had my tdo4 running on 18psi w/o any mods to the turbo. and it ran great.