will regular driveshafts from a 1.8 model fit onto this diff or do i need to get the whole rear end including axels an bearing carriers?

No they won't. Do a bit of a search around here on Sierra diffs, it has been discussed (at great length!) here before!
Good Luck.

Actually they will. People have done experiments and drum braked tripode shafts will indeed fit into an XR4x4 diff. All you have to do is open it up and free the circlip holding the stub shafts that the CV joints bolt to on the XR4x4, then remove those and the tripode shafts should push right in.

Sorry about that I *now* remember a previous discussion about this.
http://www.locostbuilders.co.uk/viewthread.php?tid=9122&page=1

My apologies.

they will only work on one side of the diff they are short on the VC side

Wow, wrong twice in 2 posts! Is that a record?.
Hehehehehe.
I don't know, read the thread I posted above for all the details!

It can't be a record, Steve Gusterson is never right about anything...