[steveproracing]

Nothing looks way out on there but things I would try include
A rear ball diff or 20k in gear diff
Drilling rear Pistons to 1.6mm to reduce pack, same oil and spring
Playing with antisquat? If it's wanting to swap ends on corner exit then increase
If it's got plenty of grip on exit but is kicking up the rear on the bumps

Hope this helps.
If not let me know I'll try to help further