I am running a 2.25" exhaust all the way back with an N1 canister and a GSR cat(need to pass emissions and never removed). The exhaust is VERY loud but not like a can of angry bees like a D-series with an identical set up. It is LOUD but deep and solid sounding. It does get a little high pitched at full throttle and high RPM's.

Probably does not help but oh well