You'll need an adapter to go between the head unit and the rest of the system - I think they're $60-$100 (US) depending on the brand and 'extra features'.

The factory CD player has a proprietary interface, so while it MAY be possible to rewire and rig, it's probably really difficult at best. I wouldn't bother - Just pull it out and get a panel to block the extra DIN slot.

If you're not wanting to spend the extra money for an amp, the 460 should do the trick. It's not as great as what you COULD get, but it's not that bad IMHO. In fact, I had planned on using the MACH 460 in my '98 with the empeg, but got rid of the car. The new car didn't have @#$* for a stereo, so I built from scratch.

Hope this helps.