12-15psi should be good pressure wise, if you've never run on pressures that low before you may want to start higher and go down to get used to it. I'm not sure how unstable the radials are compared to regular ET Streets but I suspect they should have stiffer sidewalls and a more stable ride. Is your sport clutch the 6 puck? I've launched as high as 7k, but I was willing to abuse my clutch.