RUSS – yes I too spent several hours this Sat & Sun trying to either a) break 4.1 or b) have a car that did not jack-rabbit in the straights or fishtail in the corners. The Supergrips marbled a little and contributed to both the jumps and slides.
After too many 4.4s, I switched back from the 22k motor to the 25k OEM motor; and went back and forth from the 32z (OEM) to 31z spurs. With the 32z I could barely break high 4.3s; with the 31z I clocked a few mid and high 4.2s but mainly stayed in the 4.3s My pinion is a 11z (OEM spec).
I also experienced more rubbing on the front tires (I need to double-check to see if I am running the 17mm or 19mm NSR-No-Grips)
"... get on your bad motor scooter and ride!"
Sammy with Montrose