Quietting down Akra Evo ...
I bought a used Akra Evo (full system) from a forum member here. While the sound is perfect at most RPMs. The Akra has a deep growl during idle (~800rpm). It also has a resonance at 1-1,200rpm. Parking underground is literally scary. The echo is insane. Has anyone tried adding additional resonators to quiet the Akra down a bit? Looking at the system, the very front section of the Akra might fit two resonators.
Any advice is appreciated.