...at TireRack:
http://www.tirerack.com/tires/tires.jsp?tireMake=Kumho&tireModel=Ecsta+XS
Interestingly, the TireRack doesn't have treadwear ratings listed, but Kumho's site says the UTQG is 180 AA/A.
I'll be ordering my set in 235/40R18 soon! Pricing is $2 cheaper than per tire in that size...