Amps have little to do with SQ as DBfan said, power is for the most part just power. Reliability is a big reason for price differences. Your deck factors in ALOT more than amps for SQ, if your deck is sending a shiddy signal to your amps, no, your "awesome" arc amps are not going to make it sound good, it will just amplify that crappy signal. Get it? Learn it. Amps are alot of marketting too. Like some of you think, more expensive must mean it sounds better, so you buy it not even knowing the science behind it. Stripped down, a legacy and a Mcintosh a/b sound the same at every given power output. Extra circuitry (eqs, x-overs, etc..) can factor in, making amps sound different when not stripped down tho. THD in amps is stupid to look at BTW, even your high end speakers have A TON more distortion than the measely .01 or whatever an amp might have.