In time the check light may go on, its cause of the back pressure when a sports exhaust is fitted, but it shouldnt affect how the engine is running. My check engine light use to come on every 2-3 months with sports cats but since i changed my system to straight through pipes that problem has gone and it now sounds like F1 car :-)

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Dont lean on my car unless your butt naked lady! No scraches, scrapes, allowed doesnt matter how hot you are

My Vehicles:

Lamborghini Murcielago e-gear 2006
Lancia Delta Integrale Evo 2
Bmw X5 4.6is with supercharger
Mv Agusta 1000 F4
Bmw 645 Ci Convertible