i just found this write up last night. looking for a aux hook up for the regal. How you can add an aux input/mp3 player without an adapter - LS1TECH

if you read through all 27 pages, around page 25 i think, they talk about using wires 4 and 5, and that jumps the radio signal. vs the cd player. best part is if it dont work, all it takes two wires to be soldered back together and it back to normal.

im thinking of popping my radio out and seeing if my guts look the same or close enough to try this.