The hyper diffs are pretty durable, is it the inner gears stripping ? if so shims wont help, maybe the seal is loose .. you do have oil in them ? If you want a front diff that takes a pounding get a Torsen front diff.. they last ages.. Ofna distribute one, just as good as the fioroni IMO.. they just dont look anywhere near as nice.. about 60 US on ebay

If its your crown gear stripping then you may have a shim problem, it could also be your diff housing. check the whole assembly is in tack , if you have some screws loose your housing wont hold the diff in place..

Hope this helps..