04 Colorado Budget System

Can anyone tell me if I'm on track or what potential flaws there are with my plan. My intent is to use the stock deck and speakers in an 04 Std. Cab Colorado and add a crossover, 4 ch. amp and a sub. The gear is what I already have laying around: early model JL12W6, Precision Power A404, MTX RT-X01A crossover. I plan to use the two speaker level inputs on the MTX (the stock deck only has a balance control and no rear speakers so I assume this is only a two channel deck) and output the four channels on the MTX to the amp. The front two channels will be to the stock door speakers utilizing a high pass on the MTX and the rear channels will be BRIDGED to the sub, utilizing the low pass on the MTX. Some tech support I could use: -I need to run a remote power wire to the amp and crossover and don't know which one to tap into on the 04 Colorado. -The sub is a dual coil. Which wiring configuration should I use on the speaker, paralell or series? -At what frequencies should I set the crossover dials on the MTX. -Is this stereo really a two channel, or because it only has two speakers hooked up, it thinks and acts like a two channel stereo? (the balance, tone etc. controls are electronic rather than a knob or dial) It doesn't make sense to me that a manufacturer would have two seperate stereos installed in the same model based on the cab configuration. balsimo