Audio Systems: infinity, jeep grand cherokee, polk audio speakers

Question
I have a 1997 Jeep Grand Cherokee Limited with the Infinity Gold Sound. I purchased 6 1/2" Polk Audio speakers for the doors and I would assume that they should be pretty basic to install. However, I also have an amp and Bandpass box I would like to install as well. I was hoping to not have to change my head unit though. I was wondering if there is a way to get an RCA line out of my stock head unit ? Better yet, from somewhere in the back where I would assume the factory amp is ? Is this possible without too much trouble. I would prefer not to take my dash apart and remove my head unit. I know there are speaker wire to rca line adapters but I dont know how it would work without using up the speaker wire. Is the speaker wire supposed to be split ?

Answer
you can not use pol audio speakers in this vehicle
only factory infinity speakers , don't waste your time it will sound horrible
about the hi and low yes it is possible but needs to be done behind the factory radio  taping in to the rear speaker signal wiring