These tires are Michelin Pilot Super Sport Ultra-High Performance summer tires with only 6,000 miles on them.
Their staggered sizing is 225/40R18 92Y XL for the front and 255/35/R18 94Y XL for the rear.
The tires were bought on 7/24/14 (I have the Costco invoice), used during the summer of 2014 by the previous owner, then taken off for the winter, and were never remounted. I purchased the tires from another MBWorld member last year, but traded my own C300 before I ever had a chance to use them. They've been kept in climate controlled storage by myself and the previous owner since 2014.
The same set of 4 currently sells for $825.50 on TireRack, plus tax and shipping.
Asking $300 for the set, plus shipping (unless you live within driving distance of Detroit).
[please note: the tires are mounted to OEM AMG wheels in the photos. Unlike the tires, the wheels need some refurbishment and can be had at a significant discount before I get them refinished and put them up on eBay. PM me if you're interested in purchasing the wheels separately]
Slideshow: A one-of-one U.S.-spec Mercedes-Benz SLR McLaren Roadster became even rarer after a factory-backed transformation at McLaren's headquarters.