What is the difference between clean amps and bad amps?

honestly, if you really want power dont worry about the brands that charge dollar per watt. the real underground/ competitors dont all use the high dollar brands but brands like audiobahn, boss, some real cheapos even use pyle, but all in all, the more you spend you are more than likely buying the name, not the output. i currently have a boss audio ph 5000d does 5k watts at 1 ohm and only paid 150 for it and its pushing my 2 lanzar opti1533d's just fine. my subs are 6k max and 3k rms so like i said, dont buy brands that are dollar per watt, cuz if i did, then i would be spending my yearly salary on a car system