There are basically 2 versions. With or without coated shafts, shock bodies and rod guide set.
There are also 2 different piston lengths.
Coated only available in one length front/rear though.
201 comes with all options. 511 and 502X with the parts you have.
Coated shaft and shock bodies are supposed to have lower friction. Not sure if they are worth upgrading performance wise. Bit bling of course.
Maybe top guys notice the difference, who knows.
