im ungrading my car audio amplifier.i want to have a good quality amp that i can play as loud as i want it to. what should i be aware of be4 buying it? any advice?

 

The biggest car audio systems have amps that use the pre-amp outputs to daisy chain a large number of amps together to power a large number of subwoofers or full range speakers.
A build in crossover is great for a subwoofer amplifier.

 

give us a rundown of the entire system and it will be much easier to advise you. we dont know if you need a 2 or 4 channel amp, or how much power would be suitable for the speakers you have, how many pre-outs your head unit has, etc..