New bushes should see it handling like a gokart
Mine do

Changing the spring will only play around with your height ... making it stiffer will make the handling worse... they are bumpy enough as it is
Though I do have gas shocks in mine which have stiffer setup than the oily's

Dial some neg camber into it and get the radial rods screwed right in (after clearancing for tyres) and it should track alot better