I mounted -06 R6 rear shock on my FZR. It is fully adjustable and this mod will increase drivability to new century.
The mod is quite easy to make. Only special tool you need is spring clamps.
R6 shock is aproximately 5 mm shorter, but it does not cause problems.
Upper mounting hole must be drilled 10 -> 12 mm.
Lower end goes directly in the standard relay arm, as long as corner is slightly rounded like in the picture.
Sitting on the bike showed that R6 spring was little too loose. So I decided to fit FZR spring to R6 shock because FZR spring is stiffer. Maybe if you are lightweight and you like driving without passenger the R6 spring might be ok. Internal diameter of the springs are comletely identical. FZR spring is 1 cm longer. I cutted about 1,5 cm piece from each side of the fzr spring and grinded the top to flat.
Now both springs are same lenght

After 12000 km it is still working perfectly











