ok heres the deal.
1.6 = dinky diff made of f uc kin plastic. not really but a very weak rear end
1.8 = Better more reliable and availible Torson
I Just swaped to a 1.8L subframe. Much stronger. I blew 5 1.6 diffs last year.
DO NOT SWAP THE 1.6 in! Get a real internal peice (KAAZ) from tougefactory.com they have a special. 825 SHIPPED!