FYI: I'm replacing the entire system, but its gonna be a few weeks before I get my amp/replacement speakers in.

Will my new Alpine head unit work "ok" with my existing Monsoon amps/speakers. When I say ok, it can't possibly sound any worse then it does now, or can it?

 

Check to see if your Alpine h/u's amp is 2 ohm compatible, if not your sunk. The tweeters in the front run off the stock head unit while every thing else runs off the Monsoon amp.