i have done some exaughst done on my. car i cant think why going to 3 inch pipe on a v6 or a v8 if there isnt much done to it. cai and headers are a start but its not much my opinion your car will sound little raspy on the inside. get some dynomat to put into your trunk and floor boards it will help keep out the raspy high pitch when out on the high way but 3 inch what have you done in mods to the engine??? or computer to compinsate for the big pipe????

 

on my car ive got stock mufflers & cat with the resinator & u bend delete & it sounds good, but if ur goin for power look in moding other areas first i learned that on my truck went threw 6 diff exhausts before it finally worked out right