Re: Need help picking either 6x9 or 6 1/2 rear speakers.
Instead of spending the money on front speakers, back speakers, and enclosures... I highly recommend getting a set of component speakers for the front that can handle a decent amount of power. Loud comps up front > coax's all around. I've had the exact same highs setup that you are preparing to go with.... and I now have what I am suggesting. Believe me when I say it is a HUGE step up in volume, clarity, and imaging.
Source: Pioneer DEH-80PRS
Front stage: PHD FB6.1 Pro & Vifa XT25BG60-04 on a Kenwood XR-4S
Sub stage: 2 Tantric HD12's on an Autotek MM 4000.1d
Electrical: 310 amp (lol...) Singer Alternator, 2 Wėrker 125ah batteries in back, +/- runs in Monster Cable 1/0