i did it...it worked great (aside from the fact that my sony sub is junk). Like they said, all i used is a radio shack line-0ut converter (radio shack part number 12-1338, i spliced it in right behind the radio..the radio can be shoved back into its slot with the line converter behind it) it has adjustable gains on it which really helps filter out distortion IMO. after that peice, everything else is the same....wiring, mounting, setting levels, is normal..
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