Less power, less gears, no manual clutch, and possibly a drop in a few CCs.
The XRs have a better cam, a popular mod is to swap the cam from a 200X with one from an XR for more power.
An on not being sure of the engine, S will have no hi/lo like an ES will, and an X will be manual clutch. Also, the ES will have an electric starter on it.
This is my trike. There are many like it but this one is mine. My trike is my best friend, and it is my life. I must master it as I must master myself. My trike without me is useless. Without my trike, I am useless. I must ride my trike true. My trike and I know that what counts is not the amount of miles we ride, but the time we ride together. My trike is human in it's own ways, therefore I will learn it as my brother. I will learn it's weaknesses, it's strengths, it's parts, and it's soul.