Any smog block off kit will be sufficient.
You don't need the externally adjustable fuel screw, but you might use it every now and then if you change altitude or temperature drastically. Really, you can set your fuel screw once and not need to touch it, unless you are a compulsive fiddler.
You don't need the JD kit. All of the recommended jet sizes are out there, and I would start at a 148 on your bike.
The biggest improvement to a 250X is an R cam.
The smog block off kits, why does the Tokyo Mods have more parts to it then? I know block offs are block offs and plugs are plugs but don’t want to be missing something I could use. I can’t find any explanation online either.
I’m going to use the R&D remote screw I guess. I will be riding in a verity of temps and altitudes. I like to fiddle too.
The R cam may be in my future but right away I want to open the air box, jet it correctly, FMF pipe, de-smog, EE (probably) skid plate and hand guards, Trail Tech Vapor and a shop manual.