TTI exhaust too loud

My Buddy has the TTI setup on his Dart with the Dynomax that came wiith the system and he is starting to complain more and more also about the resonance/drone effect at around 2000 - 2500 rpm range. His system is about 4 years old and it gets louder every year! He's now thinking of changing out his mufflers to something less noisy!

I have the TTI/Dynomax set up (2.5 inch) on my Dart Sport 340, and that's my reaction, too. This system is MUCH louder than the old Sonic Turbos and stock pipes I ran back in the day. Are the Accurate Exhaust mufflers that much quieter than the Dynomax? If so, I may have to investigate them.