Just installed mine! Took me about 2.5 hours, but I did have to open the radio back up and tape up my audio cable connector. The gold at the end of the cable (radio shack gold 1/8" cable) was touching the metal box inside of the radio - which caused a noticable hum. Once I wrapped some electrical tape around it and re-installed, everything sounds great!
[EDIT -- I would also like to add that the removal of the grounding screw on the passenger side of the radio on my radio is IMPOSSIBLE. I stripped mine out after much effort and ended up cutting the ground wire and removing the other 3 so I could rotate that bracket enough to get into the radio. I had to re-attach a post mount for the ground wire - which I screwed onto one of the other non-stripped screws.]
Anyway - This mod is AWESEOME AWESOME AWESOME! Instructions are detailed with pics, and Jazzy even provides the blank disc to play in your CD player. I am getting a slight ground loop hum from my Belkin power adapter, but only when the volume on the radio is up to like 27 or so, with nothing playing -- I dont think I will notice it when Im driving. If I do, I can just unplug the power adapter.
THANKS AGAIN! THIS TOOK CARE OF MY BY FAR #1 (and only real) GRIPE ABOUT MY LEGACY!!!!!!