Positive vote for Renns!
I ran them (RS2 - green) on my 1k for a track day last fall at Putnam Park. Awesome tires. I'm no expert or anything, but had no hint of traction loss all day. I could even move around a little at the apex, knee down and they never wiggled or anything. Tried to make the rear spin on an exit and it just wheelied instead while I was leaned over. I still have another track day left on them too. Willow is extremely hard on tires (most say it's THE most abrasive track). My brother rides there frequently, and on his 1K he gets 1 track day on a set before they're toast, he uses 208's. As I get more comfy on the track though, may try the RS1 (blue) front. My green front looks nearly new after 1 track day. Guess that means I'm not pushing hard enough?