I had KDW's. The increase noise wasn't that bad. Did 2 full seasons of autocross on them and daily driving 20k before they were bald. If you want ultimate stick go with the Falken Azenis.
I've had KDWs and KDW2s The 2s are way better. The best tire I have ever owned by a long long long way. Much better than my 300+ dollar Pilot Sports. I dont ever plan on running anything else. These tires blew me away. I dont notice any noise. How can you hear tires over your exhaust anyway??
I've never tried the KDW's, but I've had the KDW2's since January '07 and I love them to death. The sales guy said that they wouldn't last long no matter how I drive, but they've still got plenty of tread life on them.
As for noise, they are quieter than my last tires - Eagle F1 Run-flats. I'm pretty used to road noise though.
Thanks again for all the insight fellas good and bad. Right now according to the Tirerack website the KDW's are on out of stock in the warehouses closest to me. I'm going to do a bit more checking around and see if any local places can/will match/beat their price.