I have a 97 ps. 4x4 withnautomatic trans that was beefed up when rebuilt what they could and new torgue converter that the transmission tech recmended (I don't know the specs of either). I have added a 3' down pipe at the turbo to my stock exhaust system minus cat converter. Installed a LARGE trans cooler that when pulling my 30' fifth wheel seldom go past 170 and just driving stays around 140 verified by laser temp probe on pan (sender in pan) Have installed pyrometer to keed tabs on exhaust temp. have installed K&N air element.
I am just trying the little /cheap stuff before going to the higher dollar items