Kashima coat or not?
I would 


Make sure your sag is set correctly. See fork manual.
Place a zip-tie on your fork leg to act as a max-travel gauge, it lets you see how far from bottoming out you were on any ride and will aid you with tuning.
Play with the compression/rebound settings on your current fork. If ride is too harsh, reduce both.
If you are unable to smooth out the ride, or it is at the expense of a wallowy ride, have them serviced (new oil, seals as needed etc).
Avoid large-bill outlays on the current fork while saving up for a better fork in case you can't improve the ride enough. You fork (and bike) will have some resale value, but putting money into it won't increase the resale value.