The stickiest street tires I've used are Kumho XS y Hankook RS-3. I didn't like the Pilot Sport Cups. Most R compound tires require -3º of camber on the front as a starting point so before considering R compound you'll need to buy something like KMAC's for the front.

I'll be using Hankook Z214's at my next event an I'll let you know what I learn. My car has -2.5º front camber and -1.5º rear camber as a starting point because that's what worked best with the Kumho's and Hankook street tires at the track.

Les