Seen these on various US websites, street legal tyres desgined to compete against Renns/SCs/D208GPAs etc, I've always preferred bridgestones, and they come in the holy grail of tyre sizes

, a 190/55.
Anyone used them, and where can I get a pair at a good price?
Curious cos I have never seen them on trackday/race bikes, was wondering if there's a good reason for that!
