I would actually expect a very good life out of them. While I've had a set of Michelin XGT-V's(extremely soft tires) that wore out in 7000 miles, the Michelins that came on my Miata lasted 24,000 miles. This includes a lot of tail out driving and an autocross school. I have switched my fronts to 245/40 Pilot Sports to make it more balanced and I have been pushing it very hard in corners. I am still surprised at how good the turn-in is despite the cars weight and wheelbase. I would have expected the car to be camber limited from the factory like most are, but I'm not rolling over at all. In fact, I haven't even work the nipples off either side of the tires. Infiniti/Nissan has done a great job getting the camber right to put the maximum contract patch on the ground. This increases the grip, allows even wear across the tire and extends tire life. I would expect about 25,000 miles out of my first set with aggressive driving.

04' G35 Coupe(finally in the garage)
6-sp Diamond Graphite/Willow w/Premium

 

RamboRami, I've heard of that tire-swapping rotation. But I heard that's not such a great idea because the tires wear from the inside out or something along those lines.
How do I measure the wear of my tires???