I think you forgot to mention one other important feature of the Biketronics unit. The BT 480 has a lifetime warranty.

I think part of the sound quality may have to do with the speakers you used. I installed the BT amp with their Biketronics Titan XL 6.5" speakers which are a better match than the speakers you tested with. The Titans are made in Italy and also have a lifetime warranty. I don't know what the warranty is on the ARC unit or the speakers you used in your comparison.

When riding my bike with a modified engine and 2:1 exhaust (loud), I never have to operate the audio over 75% at any speed. I find the fidelity of the sound to be excellent but to be honest, fidelity at 70mph is somewhat irrelevant given all the ambient sound.

I found the BT unit to be easy to install, small and produces both excellent sound and volume with their matched speakers. Add in a lifetime warranty and the BT package is a hard combination to beat and that's why I went with them.

 

i have gone through 3 sets of Polk 5 1/4 speakers with the biketronics amp, I just blew the left speaker riding to yuma last week i dont crank my system-my volume is set to the "L" on the word volume- my AVC is set to 2.

im lookin to bump either to the 6 1/2 hertz or the 7 1/4" JM speakers

The reason i heard the prob with the biketronics amp is the crossovers have "no gain" adjustment.