I have the 3" and you'll need it for your HP/TQ to decrease the back pressure. Remember, at highway speeds you'll hear more wind noise than the exhaust. I love my system, size, increased HP & TQ,......and the great noise. Plus, in a Cobra, expect it !
I personally think if anyone complains about the noise, or as far as that goes, wind and rough ride, sell it for a Cadillac.
