Tyre wear seems to be a known problem with the quattro (permanent four wheel drive) system.
I tow with a lowly 1.9tdi A4 Avant quattro sport with 235/45 17"
tyres.
On the original Continentals and subsequent Michelin Sports I got 11,000-12,000 miles per set of four (rotating to equalize wear)This was apparently due to the soft rubber on the supplied sport tyres.
I now fit BF Goodrich tyres.These are the same size,but as a non-premium tyre have harder rubber.I get 18,000-20,000 miles per set of four.I am told that Michelin own BF Goodrich and the tyres utilise a carcass off an earlier version of the Michelin sport.Either way I get a set of 4 for