QUOTE(Tyler @ Dec 23 2007, 04:00 AM)

While I have not messed with a Monsoon system I'll bet the 4 wire plug is for the woofer and the tweeter. I would see if any two wires would power an aftermarket speaker ok. I bet it will. If the size is like a non-Monsoon system the speakers are 6 1/2". Pioneers fit perfect,screw holes and all.
I tried some after market speakers in the sail panels a few years ago. it was a no go. The replacement speakers that i tried were 6 1/2" Crunchfield if I remember correctly. The 2 wire speakers dont pick up enough watts for the 4 wire speaker or something else that Im not catching onto. The sound was horrible and you could barely hear anything coming outta of the speaker. Bottom like scenario, you gotta replace the whole head unit to use 2 wire speakers.