Phil Walker asked
  I'm looking for a
  way to get another audio input into the stereo system without having to buy
  another head unit (I like the stock one and want to be stealth). Is it
  possible to find an amp that will take two inputs? 
You can buy an audio video A/B/C/D switchbox at Radio Shack for about $25 and ignore the yellow Video jacks. (Cat. #15-1956) They are mechanical and so require no electrical power.  They give you 4 ins and one out.  You can use ordinary pre-made RCA plug audio cable (or pay more for gold plated ones that shouldn't corrode) from the same source. Mount the box somewhere with velcro (maybe in the Glovebox?).
Tom Scott
84 Westy