Um I know what CarPC is, its been out for years... but you're telling the guy to get a new stereo? Or get to get a Car Computer?? Thats $$$ No... Just use the link I posted. Its a cigarette lighter powered A2DP Bluetooth FM Transmitter with handsfree speakerphone for ANY car stereo for $100 Bucks. All he wants to do is accomplish what he is already doing without wires. Thats using his Mogul as a MP3 player for the car.
http://satechi.com/Bluetooth-Handsfr...B000KJBNEI.htm
Here's a YouTube video from the manufacturer (Satechi).
http://youtube.com/watch?v=FDPiAq2H0aE
I admit its relatively new so you may not have known it existed. Motorola ROKR is also coming out with a visor mount version (battery powered). Motorola also has A2DP bluetooth car adapters that are hard wired to a car stereo aux or other input, but requires a professional installation.