Hey Jazzcat - how are you finding your infinity's sound? Did you go with the +3 or +0 in the end?
Maybe it's where I am positioned but the rears do contribute to my overall sound experience in the car.
You must be a tall guy with long legs and have the front seat back towards the rear. On the other hand, my legs are short so I seat close to the steering wheel. I'm getting my Infinity's tomorrow and plan on swapping out only the fronts. I already have the fader putting the sound mostly upfront, as I don't have rear passengers very often.
Modifications Performance: Airaid CAI, 93P Tune by Torq, Dynomax Exhaust Interior: Auto Headlamp Switch, Leather Seat Upgrade, Infinity Speakers, Billet Chrome: Door Locks, Radio Display Trim, Door Lock/Unlock Covers, Map Light Button Covers, Air Vent Covers Exterior: Chrome Door Handles, Faux Gas Lid Delete; 3.7 Emblems, Stock Wheels Painted Gloss Black, Tinted Lights, Dark Gray Rocker and Hood Crease Stripes, Upper and Lower Billet Grille Overlays Engine Compartment: Custom Strut Brace