I generally run 38 in my Kumho's (265-60/18), and get in the mid-300's when my NOVA commute allows me to do the speed limit. I got 43,000 miles on my last set of Kumho's, and the fronts were worn smooth all the way across. I love to haul around corners, so wearing out the fronts is not surprising. (Yes, I do rotate the tires...occasionally.)
thanks Gregg, that's encouraging about the mileage you got. I got the tires from the Tire Rack 2 years ago on the way to Jekyll and they weren't terribly bad.