I can only advertise how much these sprockets improve the R259 motor!
It's really a must have. Much more fun and a lower fuel consumption as a bonus. It's incredible.
Take à look here : http://www.spritmonitor.de/en/detail/461213.html
I have fitted the sprockets at 41000km. 1000km and 3 tankings later, my fuel usage has dropped by nearly 15% while it take more pleasure!!!