Good Quality of an Amplifier makes a great deference and produce an impressive sound.Just More Watts never makes an amplifier successful.check for such AMP brands those are at the top in users rated list.
That was a good one glass. I think lot of people get confused with power rating. A good quality amp that's 200W rms WILL sound louder and better compared to a cheap amp that's 300 - 400 W rms. In theory it doesn't make sense, but in reality, it does cause amps aren't made the same way. There are lot of factors involved in producing quality sound. Cheap amps tend to not list or emphise on useless numbers like "2000W PEAK", and .05 THD @ min power. As for your question for the best possible amp around $550, I'd go with Zapco, Orion, PPI, RF (T series), Kicker,JL, JBL, and Audiobahn HCT series. I don't know how some people can crank up 2000W of power when my 18" sub with 200W rms pounds the crap out of the car chassie and mirrors. If I ever put 500W rms, I think my muffler would fall off along with few others.