I am now installing a b16a in my ek.. i want a chipped ecu to get knock sensor and o2s disabled, the vtec starting @ 4500 and the fuel cutoff @ 9000rpm. I do want to know if there's a difference between a chipped p28 and a chipped p30..? Aslo.. I have 3 different headers.. : 1 stainless steel tri-y 2'' outlet. 1 stainless steel 4-1 2'' outlet and 1 dc sport ceramic coated 4-1 2.5'' outlet. I use a Yonaka exhaust line 2.5'' that has a restriction to 2'' to bolt on the front pipe.. the dc sports.. are the nicest.. but ive heard that if I d'ont have a small restriction near the engine: ill loose power.. any infos about that...?