I have the REDS RZ6 conversion. It was about 160 euros, and was superbly made, and took off items from my ZX6 and RB6 to convert it. Also bought a geared diff. So far, at the level I run at, it's pretty good. We run on carpet (very, very low cut, and slightly slippery with control tyres of yellow stagger fronts and white venoms for the rear