That cop was a dick though.

 

Same thing happened to me when I had my RB header, Catco high flow cat, and N1 duals.

 

I drove around all the time with a header, high flow cat, and dual 2.5" piping to blown ebay mufflers. Very tolerable, not loud at all. That high flow cat REALLY quiets down the exhaust!

Then I went to straight pipe instead of the high flow cat and... well... it was loud. Then I ported the motor and removed the exhaust diffusers, can you say painful? Had to put the borla xr-1 in after that, still insanely loud but it was tolerable.

I'm almost afraid of what it'll be like now. Bigger ports, huge exhaust port, no diffusers, header, borla xr-1, and CS catback. Oh well, the price I pay for performance...

I've also heard and driven the apexi single catback. Had a car I was working on, s4 TII, which was ported (intake and exhaust), with 3" downpipe, 3" non-resonated test pipe, and apexi single catback. Man that thing was quiet! I was driving around and it just gave a nice little tone that was completely tolerable. Granted turbos are quieter, but with all straight pipe except the single catback, I expected it to be louder. Apexi really did a good job making a single catback that is fairly quiet.