I'm trying to upgrade my system from stock for around $400. I want to get replacement speakers, amp, 8'' sub of the best quality at that price. I dont know that much about audio so I dont know which brands are good and whatnot. I have a Pioneer DEH 4400 rite now. I was looking at the infinity reference, profile amp, rockford punch he sub, but im not sure if that combo will sound good

 

the speakers are good, will work fine.... RF HE subs isnt the best, but not the worst, decent choice, you might want to look at JBL amps, good cheap power and is underrated and reliable