ok, so I measured the space available behind the seat. The kenwood amp and this pioneer sub should be able to fit on either side of the pump. I will have to raise the pump a bit to fit the sub in, but that shouldn't be a problem. The pump bracket is held in place with 2 bolts.
Shallow sealed enclosure with 8" 2-ohm subwoofer
Reference Series 5-channel car amplifier — 60 watts RMS x 4 at 4 ohms + 600 watts RMS x 1 at 2 ohms
For front speakers, I'm looking at
Excelon Series 6-1/2" component speaker system
For rear, maybe
P-Series 6-1/2" component speaker system
So I would need a wiring kit and fuse to run to the battery. I guess I would 3 sets of RCAs to run from the deck to the amp.
Is there a way I could tap into the existing speaker wires in the car for the front and rear locations, from the back where the factory amps are? or what would be the easiest way to wire it?