There are two relatively simple upgrades that you can make that will each double the resolution of the K8200.
First, consider using 0.9-degree stepper motors instead of the stock 1.8-degree motors. The stock motors are 42BYGHM811, but you can use 42BYGHM809 instead. The motors are identical in every respect, except that they have twice as many steps for one full resolution - 400 instead of 200.
The second easy upgrade is to use DRV8825 stepper controller boards in place of the 4988 stepper drivers that Velleman provides. The 8825 drivers will default to 1/32 micro-stepping instead of 1/16 micro-stepping, which will again double the resolution of any affected axes.
You then double (or quadruple) the STEPS_PER_MM setting for each upgraded axis in Configuration.h of your Marlin firmware. Of these two upgrades, the first one will yield better quality, as microstepping is not guaranteed to be linear. I have done both mods on my K8200’s and they work very well.