nope, sorry buddy but ifs surf has a smaller front diff and it can't be swapped with the back.
I have an open diff i'd swap with your lsd but i think its the wrong ratio ill have a look on friday when im back.
I'm sure someone out there will have an open diff that they'd love to swap for an lsd (assuming they dont want to run a locker) they might even give you some cash depending on condition

Never argue with an idiot, they drag you down to their level then beat you with experiance!