just wondering if its possible to run my 2 rear speakers on the deck that I havent bought yet and my 2 front components off an Alpine MPR-F550 its a channel 4, to fill the other 2 channels on the left to sub
Yes, but cheap to IM yet you say I can do this with 80 watts RMS Alpine 260-watt speakers before tip?
o and how do I go about this, what do I need?

You can, but you want to make sure that the speakers can handle the wattage. The sub will be limited to what can push the amp.

Usually people make a 4-channels to the speakers and a mono amp for sub (s).

Ok so i narrowed it down to an mtx-tc6004 and an alpine mrp-f550 there both about the same price on ebay. Im running 2 mtx 100 watt rms 200 watt peak 6x9 and 2 alpine components 80 watt rms 260 watt peak. Dont know which amp to buy Alpine has more watts with 90 watts rms and the mtx is only 75 rms but i think the mtx has less thd distortion and i read somewhere that it compares to the higher wattage amps becuase its so powerful even though the wattage is only 75 rms, Is this true? Which amps will sound better and louder?
http://cgi.ebay.com/NEW-MTX-AUDIO-TC6004 -4-CHANNEL-CAR-STEREO-AMPLIFIER-AMP_W0QQ itemZ270224833581QQihZ017QQcategoryZ3973 9QQssPageNameZWDVWQQrdZ1QQcmdZViewItem yes but read this ebay link
i like alpine , especially the speakers i bought but they have terrible bass allthough they have good mids and highs