Jeep Grand Cherokee 99

Stupid stock infinity crap, what a pain in the ass. Ok heres the deal i need some epert advice, and this is kinda the place right? alright, first, i wanna keep the stock head unit despite my original intentions. So, yesterday i got infinity component the 6.5" well i wanted the tweeters up front (makes sense right) so the 6.5"s are in the rear doors, then i got 3 way pioneers 225 watts in the front. I couldnt cash out or the time for a new amp, so im using the stock POS 2 ohm infinity 180 watt. Now, im planning on gettin a cadance 4 channel. From what ive gathered, the amp is a 6 channel infinity.  Hence my dilemma. 6.5"s are on a crossover, but the tweeters are technically with the wiring in the back and the 6x9"s are only pushing lows cause the amp. Now if i get this cadance 4 channel, i want the tweeters up on the front channel, if its worth it, but i know i really dont wanna run them off the pionners. If im downsizing to a 4 channel what am i gonna do with the wiring.

SO quick recap tweeters:

 Stock infinity 180 watt amp 2ohm 6 channel pushing pioneers 6x9"s running lows in the front. infinity component with crossover 6.5"s are in the rear doors, tweeters are in the front. How am i gonna run the system off a 4 channel with the best sound?