[Zimbo16]

6.5kg sounds a bit on the light side for the rear spring Tonio, I'd have said 8kg would be about ideal. could you try putting the original spring back on and see if that improves it? I would have said raising the rear ride height shouldn't cause problems under braking particularly, of course I may be wrong though!

Whilst you have the forks apart, measure the springs - outside and inside diameters, free length, and also the length of the spacer tube. The springs I have may well fit.