Initial report on the Sumitomo HTR-ZII tires on my C43 AMG: good appearance (central gatorback, with a rim protector). Ride comfort and road noise much better than the Michelin Pilot Sport (really excellent), but difference in cornering bite is noticeable tho still good. Wet performance is perfectly fine (70MPH through hard rainstorm without any noticeable effect).

For my driving (mostly interstate commuting and in town driving without track or autocrossing), these tires seem fine and a bargain at half the price of the Michelins, tho they are Ultimate Performance rather than Max Performance -- don't think I'll really miss the (at most) 10% performance edge. Would definitely do again, and would recommend for someone with similar usage for a high performance car.

Price all-in was $680 for four tires mounted, balanced and aligned (with disposal of old tires) by independent who does all the tire work for local Mercedes and Porsche dealers -- I let them make a bit of profit on the tires for goodwill -- they have subsequently mounted a set of Yokohama AVS Db from Tire Rack on my daughter's '88 420SEL for less than the local Tire Rack installer.