Is this post a joke or are you serious?
First, the model numbers all start with L, not SL and GL or anything else, just L.
Second, Kubota makes a great tractor. The standard L isn't for me, but I'd be happy with a Grand L. My Kioti has features a grand L doesn't and it's missing some that the grand L has. My Kioti is more capable in some ways, and less so in others. I'm assuming by "the most advance tractor built in that size range" you're talking about HST+ on the new grand L's. Yes it's impressive and I hope Kioti develops their own advanced HST. FYI Kubota wasn't the first company to develop an advanced HST transmission, so if you consider anything developed by others to be "copies" of it, you'd really have to call HST+ a copy as well.
I don't really care what Kubota names their tractors, and I'm dropping the whole thing after this post. The thing is, they're confusing even Kubota owners and fooling them into thinking they're getting the same tractor with less features. BX owners don't think they're getting the same thing a B owners even though there's some overlap of hp and there's just as big of a difference in frame size with the L and grand L.
LXX40 is a a grand L.