I just purchased the Sumitomo HTR-Z III from tire rack, really nice tire! Check tirerack.com, they beat out the mich ps2's, conti sc3's and the advan sports, all with a "300" tw rating.
BTW, treadwear ratings do not necessarily determine the life of a tire. Rubber durometer (independant of tw rating), driving style, camber/toe, tire pressure etc. can vary as well. I just got 28,500 miles on the OEM potenza re050's when they were on the wear bars. 140tw rating fwiw.

 

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