i personally have Rockford Fosgate Punch 4x6's in my front and 6x9's in the back, listen to them for about ~2hours each day, front ones have sit in the sun for awhile still trying to find some covers to put over them, i put the 6x9's cover over them, and the cover are slowing melting, but the speakers still have no problems, i spent probably ~120 total for both sets of speakers, i'm powering them with
http://a248.e.akamai.net/pix.crutchfield.com/products/2010/17/113/p113KiV900B-f_mt.jpeg and they don't really distort even on max volume, just abit hard to handle lol (and i had to put my fader to rear 6 out of twelve) seeing as the front speakers are 1/2 the power of the back ones