If you are considering the 3.2 block/2.8 head, you might check with these guys, they have a universal head stud set that
might work:
http://www.ngpracing.com/newstore/volkswagen/golf-gti-jetta-beetle/mk4/2.8-vr6-3.2-r32/engine-en-5/engine-block-components-en-12/IIRC the 2.8 and 3.2 both have head bolts, not studs, which makes things a bit tricky as the bolts are precisely sized with shank and threaded section lengths. Not sure if a stud would work, but maybe, if not you'd have to have ARP or someone similar make up a set of custom bolts.
Obviously the head height is different, with the 2.8 being shorter than the 3.2. Are the head bolts bigger in diameter on the 3.2? If they are then you'd have to have the 2.8 head bolt holes bored out to match the 3.2 head, as you couldn't do anything about the size of the threaded holes in the 3.2 block.
- Michael