Okay all I'm thanking you all ahead of time as I love this site and what it brings. Now I've thought a lot about upgrading my sound system starting with the head unit and door speakers but a big factor is the factory subwoofer, I'm very pleased with it compact wise and it's enough bass for me. I can't believe the small wiring harness that its powered by very shocking. So if I upgrade my head unit do anybody know how it is to be wired up? Is there an easy way to get it to work via subwoofer rca's? How is it gonna stay powered and remote turn On? I plan to install a zapco 4 channel amp for the door speakers behind my rear seats and it pretty much leaves no room for a secondary or subwoofer amp have a power sliding mirror motor back there to at the rear. I tested fitted a box for two 12's under my rear seats and no there isn't room for anything after all is said but no desirable place I see to put in an amp for that box I I go aftermarket sub. Any advice?

 

Put a pioneer AVH-X2700BS in my 07 FX4 Scew cab with the factory sub. You need to put a 12 to 5 volt regulator in the wiring.

http://www.crutchfield.com/p_120AFDI5V/Axxess-AFDI-5V.html?search=12+to+5+volt

Wire this to RCA's on the head unit in the sub woofer channel

http://www.crutchfield.com/p_120705521/Metra-70-5521-Receiver-Wiring-Harness.html?tp=2977

The 2 blue wires on the RCA harness need to splice into other wires on the head unit harness. I did this install a couple months ago I forgot which ones. Call crutchfeild and they can assist you. They have awesome customer service. If all else fails I'll get into my dash and take some pictures
Good luck!

 

Also the 12 to 5 volt regulater should be heat sinked to something in the dash. I just zip tied mine to the metal brackets around the center dash pieces. It's a very small regulater.

 

Thank you a lot answered well great info, one last question... Are the door speakers powered by an amplifier that I may be unaware of?

 

The door speakers are powered by the factory head unit. If you get a good aftermarket head unit they will push more power than the factory and it will sound alittle better... But aftermarket door speakers are definanlty the way to go