Looks like non-adjustable shock, so worse than stock even. People have reported good results with this shock:
https://www.progressivesuspension.co...shock-kawasaki . There was special for $175, but no more.
Maverick showed some shocks coming out of Indonesia that looked very promising. Had preload AND damping adjustments. Then again, GSXR shock has all that for $20-30 from fleabay, but requires some minor mods to fit.