A decat with the OEM exhaust doesn't give that much gains in my experience. The only gain I felt was a marginal increase towards the upper-middle portion of the rev-range all the way to the redline. The engine feels less strained too at full-song but I think this might be more psychological and actual. http://www.ltregister.f9.co.uk/graphics/happy1.gif border|EQU| 0 align|EQU| absmiddle >
My mechanic says the most crucial portion of the exhaust is the first 1 meter from the exhaust ports down just past the CAT on Evo's. Hence I suggest you also replace your downpipe when getting a full exhaust system (unless it already comes with one.)
A friend with an E5 installed an exhaust (Apex'i) and was quite dissappointed with it, as he felt he lost too much torque low-down. But after he installed the downpipe and removed the CAT, he says he is very happy with the gains in power, torque and over-all driveability. [img]http://www.ltregister.f9.co.uk/graphics/happy1.gif border|EQU| 0 align|EQU| absmiddle >