with these speakers u don't need to use an amp, if u have an 50x4 head unit or more it should be enough to power it, but if u have other components like a sub-woofer in ur car, i think u should use a small amp on the speakers to enjoy them to the fullest. and as for the quality of these speakers,i haven't tried these one specifically but me i would recommend any product of Kicker cuz in my opinion they are the best brand in car audio.