as far as neons, i'd think you'd be better off posting at a civic forum, not many people have done that to thier contours, but i'm sure someone might be able to help you out. As for installing a head unit, its super simple. Just make sure you get the right harnes (go down to circuit city and ask the install guys there to help you find the right one) and splice the wires together color to color. then remove your stock radio, and plug the new one in. If you have the premium sound package(has a CD player, most of the time) and want the best possible sound, you can go to crutchfield.com and get a factory amp bypass. Do a search in the car audio forum for more info. But installing a HU is so simple, i just can't justify paying $80 to have it done by someone else. If you can put a twistie on a garbage bag, you can install your own damn Head unit.
Silver 1998 Mystique LS (v6)...ATX

Removed Emblems, limo tint, painted calipers.
Premier P630 HU with 4 Pioneer TS-A6895 Speakers with 10' Sony sub (yeah i know, i'm cheap)
Commando 501-S Alarm