Disclaimer: I have no opinion on this one way or the other. I saw this kit and remembered reading member's posts who said they wished the rear were higher for racing. Some of that can be done with minor pre-load adjustments. As stated above, a different shock can also achieve the desired result, though at considerable expense. A riser kit MAY do the same with very little cash outlay.
The R3 has a slightly greater Rake at 25 degrees, as compared to the 24 degrees of the R6 and R1, so raising the rear (decreasing the Rake) can make the R3 handle more closely to those two more performance-oriented motorcycles.
"Observations of steering geometry show that raising the rear of the motorcycle by as little as 10 millimeters will decrease the wheelbase and the rake, allowing the motorcycle to turn faster with less effort required from the rider. Sport bikes will gain considerable maneuverability boosts by raising the rear of the motorcycle slightly. This will allow the rider to tailor his motorcycle's steering habits to the needs of the racetrack on which s/he is riding.
Raising the rear too much can alter Rake too drastically and negatively affect steering, with an increase in the possibility of causing low side crashes. If increasing rear ride height, always make changes in very small increments and observe the changes to steering feel after each change."
