Differential fluids

[SOP8920@Siena.edu]

Hey all,
    I'm planning on having my differential fluids change in the Q at the same
time that my mechanic replaces the tie-rod end. I was wondering if anyone has
any insight as to the recommended diff. Fluid. My mechanic said that he doesn't
think the diffs use anything special.. but since he isn't a Audi-specialist,
I thought it would be wise to ask the list. 
    I recall Chris Lemon saying something about how the fluid he changed to
(Amsoil?) leaks quite a bit.. 
    Keep in mind that I don't race this Q, but do drive fairly aggressively.
So what's the concensus? 
                               -Osman Parvez
                                89 200q
                                Siena College
                                Albany NY