Yesterday I bought a set of Infinity 6000CS (90W RMS) Components for the front of my SUV and a set of Infinity 6002I (60W RMS) 2-ways for the rear. I run an Alpine CDA-9831 HU and two 10 inch subs off a 2 channel 400W amp. My question is whether I need to amplify my speakers in order to make them sound good. Will the Alpine HU put out enough power to even make this speaker purchase worthwhile? If not, what size of amp do I need to power the speakers?