For what its worth, I have run Hankook 214's both 51's and 71's on a Touring 3 RX8 all season. in 2006 I ran the A6 and R6... so I have some good comparison to base it off of.
I've found them to be every bit as competitive as the Hoosiers in the Nationals. Both Hankook's and Hoosier's are great tires for the sprint races... however I have been able to get much more longevity out of the Hankooks. The RX8 is very good on tires... that said, I pushed a set to see how many heat cycles before they were junk. At 14 heat cycles (at least 20 minute practice sessions, most were at leat 30 - 40 minutes sessions) the C51's still had life to give. They had slowed slightly, but the wear was tremendous! As long as the car is set up well, the Hankook's will prove a great enduro tire!