wellpp.. from what ive seen and experienced with them they sound ok. They of course don't put out exactly what the say on the box but they are pretty solid amps if you take care of them. I have not noticed any odd noises or such from the amp though.. not from power acoustiks at least. Just get more power than you need with them and that way you will have a cusion in case it doesnt produce quite what its rated at plus it won't have to try as hard to get the right amount of power to your speakers.
I really like the PS2-520 and PS2-820 amps. Very tough and reliable...put out very close to rated power. Ranger recommended them...I tried one in my brothers car and it works flawlessly
i have 2 LT series amps they put out some power,and would barely get warm. http://i158.photobucket.com/albums/t120/PQmodean/DSCF1863.jpg