Bill,
Earlier this summer, I replaced 5 year old Kumho's with Hankook AH12's on our 99 Marquis ... after just a few thousand miles, I have no complaints. Only reason I did not put Kumhos back on was ... I couldn't find anyone that had any in the Western US to include the distributor in LA area. The Kumho's were the best riding tires we ever had on the coach over it's 146K life ... much better than the Toyos. Time will tell on the Hankooks but so far so good.