without removing the stereo you are limited to a cassette adapter or a wireless FM modulator. both will have very low/crappy sound quality.
the next step up is a wired FM modulator.. you will have to intercept the antennae connection for this.. best place is behind the stereo but you can also get to it at the antennae itself.
All you need is an FM modulator!they usually around 30 bones available everywhere.
unless you get a new radio installed, an FM modulator is your only option
should do
try www.haynes.com
No
It would be best to disconnect the battery but removing the fuse will also work as long as you are careful not to disrupt other hot wires while working in the dash.
http://www.installer.com/cars/chevrolet.html
No.
Begin by removing the decorative cover to your stereo. Remove the stereo retaining screws. Slide the stereo out and remove the wiring harness. Reverse the process to install your new stereo.
There's no such thing as a "power stereo pump", either someone is BSing you or you misheard them for something different.
purchase Haynes manual.
Good luck. I know in a '98 you have to take out the dash...