My wife and I both owned Hyundai Elantra's, but recently purchased a 2005 Toyota Prius. We found one with the Package #1 option. So in my wife's Hyundai we bought and installed an Alpine MP3, CD player with an external Sirius tuner. The Alpine has a unique feature to turn off the internal amplifier to save power and send the audio signal to the RCA outputs. What I wanted to do was continue to use the MP3 player and Sirius tuner on the Alpine and play it through the original factory radio. The original radio did not come with a CD changer and so that was where I wanted to connect the RCA inputs. I used a PAC Aux-box, with the vehicle specific cables of AB-TOY and AB-TOYT. I just put this in about a week ago and it worked perfectly. The Alpine unit fit perfectly into the cubby hole below the factory radio, and it didn't require a mounting kit or any other type of adapters. The wiring I connected was the Power, Switched Power and Ground. I hard wired these into the factory wiring harness. Then I connected the Alpine's RCA outputs to the Aux-Box and the cables to the Prius radio. It works perfectly. It isn't anything fancy and to see the Sirius radio display you look at the alpine but it was cheaper then many of the alternatives. The total cost for the Aux-Box and cables was 120 and the rest I already had. PAC was the only company who would verify their products worked for the 05 Prius, so that was the way I went. I just though I would put this out there and if anyone has any questions then feel free to email me.