how much of the front end is similar or interchangable? are the lower control arms the same lengths?

Have a look at some of Jezza's posts.

He is in the process of doing it.
Other wise Steve C had heaps of Porsche bits on his.
ALex Holzl as well (well dad might know :thumb )

Also try SBO - its a new link so try here

http://www.superbeetlesonly.com/forum/index.php?showforum=15 

also look at http://www.germanlook.com 
Heaps of tech articles on 944 brakes on supers.