[Abrasive]

So, the amp I bought to run my front stage is a dud, so it's gotta go back.
Looking for some advice on what I should get to replace it.
Here's what I'm running:
2013 F150 Supercrew
JBL MS-8 behind the factory amp
Front:Silver flute 6.5" woofers and Seas Prestige tweeters
Rear: Silver flute 6.5" woofers (not installed yet)
Sub: Alpine MRX-M110 (1100W @2ohm) and Sundown SD-2 10" in vented enclosure (tuned to ~33Hz)

My original plan was to run my amp at 50W x 4 to the fronts, then run the rears off the MS-8. Since that amp isn't going to work (Lots of hissing and noise), I'm looking at other options.
Right now I have a friend's Alpine MRP-F450 in there, and it sounds good, and the overall volume is fine.
So here are my options:
-P900.4, or another 4 channel for around the same price
or
-P900.5 + Earthquake SWS-6.5x to replace the Silverflutes. These would just go into the rear doors of my truck. The rear doors are covered in sound deadening with high density foam/vinyl decoupler between the door and the panel already.

Opinions are greatly appreciated. Alternative ideas are also greatly appeciated. I;m already overbudget on this project, so I'd like to keep costs down, but I'll spend a little more if it's worhwhile.

 

[BIGMIKE]

The P900.4 is a great amp for the $, kind of hard to beat as far as value. I think you will find adding subs to the rear doors will be counter productive. Not sure you will get much from them other than pulling the sound stage to the rear. I also thought about installing rear fill in my quad cab but was talked out of it, and i have an Alpine h701. I would get a good 4 channel and focus on your front stage, im pretty sure you wont miss the rears. If you are dead set on running them, just run the 2nd set of Silver Flutes off of the head unit power, they have pretty good sensitivity. Just my .02, im no where near as experienced as a lot of the folks around here. Maybe someone else has a better suggestion.