Actually the dash should be the same because the tweeters sit where the speaker grill is and its a cut down version of the normal one to allow the b and o tweeters fitment.
I believe there was a thread on here about it as the grill needed painting.
Either way it would be a massive undertaking and the wiring would be the biggest ball ache.
Have a look to see what part of the b & o wiring looks like
http://forum.a8parts.co.uk/showthread.php?t=7611