I put 3900 last year on my brand new 718 Boxster and wore our the rear Goodyear tires. I drive aggressively, but do not track my car or peel out. I contacted Goodyear and they covered 90% of the replacement cost. Porsche then called me doing one of their scheduled new owner curtesy calls and I explained the situation thinking they might want to use a different tire for their OEM equipment. They ended up covering the other 10%, so my replacement tires ended up being free. It might be worth a call to both the tire manufacturer and Porsche customer service.