Adrian wrote:

3) Grab audio to mp3 format, and diy an electronics solution to play
mp3's in the 'new' car. Thinking of an mp3 player with line in and
removable memory cards, combined with a simple homebrewed power amp /
psu tucked away in the car somewhere. (There's the DIY angle !!)

-- drawback ... don't know ?? - price of the MP3 player perhaps ?
--advantages - playback is 'bump-proof' - combination of Irish roads
and 1960's Moggie suspension might cause problems for a conventional
in-car CD player..

Go for option 3, but buy a car stereo that can read directly from SD
cards and USB sticks. These are becoming increasingly common, e.g.

http://cgi.ebay.co.uk/VR3-USB-SD-MP3...QQcmdZViewItem

--
Grunff
Low temperature Stirling engine:
http://www.shinyshack.com/product.php?prid=211027