I had my RT660's since May and they've seen four parking lot AutoX events and one school lapping day at Mosport GP. Very happy with them compared to my previous RT615K+. I'm competitive in my AutoX class up there with my peers on RE-71R's, even won my class on the last event. Steering inputs with the RT660 is not darty as I would expect from a performance tire, so that's probably why experts who have compared them say that the RE-71R are the sharper tire.
With that said, the RT660's grip at the limit is still phenomenal.
My specs:
225/45R17 on 17x8" ET45 wheels.
Hot tire pressures: F=32PSI, R=30PSI
BRZ tS with Bilstein B6's.
-1.9deg front camber, -1.0deg rear camber.
Front 22mm Perrin Sway bar on Soft setting.
On a side note, I also have the issue with the cut across the entire width of my tire. I only inspected them after my first AutoX event and at first I thought this cut was created by the terrible broken pavement at the venue. The cut is pretty shallow fortunately and should wear away eventually.
