Thanks for the comments guys - Interesting stuff about cutting the board size down!!
I'm going to do without AM/FM tuner since I don't really listen much to radio, however I guess I may add a USB tuner to the CarPC if I miss it too much
Alan, you may be interested to watch the development of this thread;
http://www.mp3car.com/vbulletin/car-...kit-amp-2.html
Its regarding auto-unmuting the amp via the Serial port of the CarPC.. not going too great at the moment but I've got a member on here helping out who really seems to know his stuff!