Car Stereos: 2000 ford escort zx2 amp aftermarket repacement, ford escort zx2, premium sound system

Question
I have a 2000 Ford Escort zx2 with the premium sound system.  I was wandering if there is a replacement for the factory amp.  All I know it i mounted underneath the drivers side seat.  I do not know how much power it is rated at or anything.  I would like to keep the factory stereo because it came with cassette and a 6 disc changer in the trunk but would like to make it a little better sounding.  i know that replacing the factory speakers is the first step but was wondering about the factory amp.  Thank You for your time.

Answer
I would just add an amp between the factory amp and the new speakers.  If you really want to replace the factory amp, I would go to an online forum for ZX2's and see if anyone there has experience with replacing them.  I am sure it is pretty cut and dry, but I do not have the exact wiring diagram, and that is something you will need to wire in the new amp.  Hope this helps, Scott