[pr3dict]

I believe subbthump makes a replacement amp kit for non ba systems. The issue if I remember correctly is that you lose the center channel. As for everything else, you should be fine without a signal processor. Getting the sub installed will be straight forward, grab the wires from the rear and get the signal from them and then the amplifier that you get from wherever you get it should be able to have a filter on it to isolate the low frequencies...

Also don't worry about upgrading the rears for awhile. It should sound great without them. All sound stages the I know of in music is stereo and mostly all concerts you watch are I'm front of you. So keeping the sound up front is where you want it. Unless you are watching a movie in your car Idk if you need a 5 channel amplifier. That basically means it can send 5 different signals to 5 different places at the same time. Other then a movie what will you be listening to that has that much different stuff going on? Get a nice 2 channel or 4 channel personally.

Also, anyone know what gauge wires are in the non ba system? I usually run new speaker wires in my personal installs.