i have a standard cherokee that had the infinity system ... probably the same amp as yours ... what i found was that it wasn't a very powerful amplifier ... as the head unit already acts as a preamp and so the stock amp just gives the signal a little extra boost and i think it also acts as the crossover for the stock tweeters.
Anyway ... it's worth a try. I ditched the amp because i didn't think it'd be powerfull enough, but i barely have to turn the gain on my amps up at all. Dunno if my amps are really good or the signal from my extigy is really hot.
Either way, if you can interface with it, give it a try ... you can always change later.