I heard the same thing about the KD's and went with a set ...hoping to eliminate needing a separate set of tires for street & autoX. They are a better dry street tire than the stock F1's, look cool and do a good job of protecting the rim, but you give up some ride and they tend to be dartier.

For autoX though, the difference between street tires and "sticky" tires ...I now use Kumho Victoracers .... is day and night. I've move from top 20 finishes to top 10 finishes in tougher competition with the only change being the tires.

My next street tires will be a balance of price, dry & wet performance, and expected life.