best over all thing to do is replace the radio. your talking about a deck that is 10 years old and the changer if you have one doesn't even play mp3. if your deck has the optional mbus style plug in the back the new deck will have to be rewired. but if it has the harness wired style plug then you can blow threw it and keep the factory amp. most any car mobile place could do this but if you have some wiring knowledge then you may be able to tackle this with minimum effort. (ME) as a mobile installer would charge a 100 bucks for a rewire plus the deck install plus materials. all you would be doing to rewire the deck bypassing the amp would be catching all your speakers leads at the amp and running them to the deck unless you decide to do a 4 channel amp which would allow you better over all sound plus a easier install since the amp can be placed in the rear. so by doing this you will have to run a 4 channel rca to the rear and run the speaker leads to the amp instead of running them to the front.