Well it really doesn't matter what you want to do with it..Since the Factory amp is going to be running it there shouldn't be any problem..Kat is right also..i mean you just dumped a few hundred bucks on some new speakers and a few hundred more on a deck so you might as well replace that too...it is going to be a B*&^% to do though..
Have you decided what your going to do with the wiring? Are you going to just re-wire the system or get that wire harness i suggested from
www.installer.com? BTW what kind of speakers are you going to be putting in there and what kind of head unit have you picked out? I have a 1993 Eldorado that i put in a Alpine CDA-9811. This thing does it all..It has a built in Crossover that i can adjust and it also has built in Time correction which i can adjust aswell..Man this deck rocks!!! It also has a seperate sub out so i can add a sub and a amp and control it from the deck, without having to re-wire the system due to adding another amp..XM ready changer control Tilt face...What can i say this head unit ROCKS !!! Good luck