Don't know about the replacement of the wood look trim, but I can help with your stereo.....
The standard fit stuff is basically two standard (DIN) shaped units, so you need the VW odment tray that is common across the whole VW range. This locks into place where the CD player sits, leaving you one standard DIN hole for an aftermarket head unit.
The service manager at VW gave me one he had laying around in the workshop, but if you have to pay, expect about ?15.
Alternatively you could buy a blanking plate, but a) they look a bit pants and b) its a waste of space - the odments tray is handy for storing all sorts of, well, odments I guess. It even has a grippy rubber base, so you don't loose everything when pulling g's round a roundabout!
