What is the X-50?

The X-50 is an upgradable X Axis for your existing Onefinity CNC. Featuring large 50mm Hollow Linear Motion Shafts for great rigidity, a larger Stepper Motor with up to 40% more torque, and a 1616 Ball Screw that delivers 60% more speed. The X-50 series is available in all three rail lengths, Machinist - 16", Woodworker - 32" and Journeyman - 48".

The product description states, “optional 1616 Ball Screw that delivers 60% more speed.” Is it included as your post suggests or an add on?

Does that mean I could upgrade my machinist to 16x32 now?
I guess upgrading to a newer Xrail would give you faster rapid moves but not sure what else the increased speed buys you.

How does the X-50 compare to the X-35 with a stiffy 3rd rail in terms of rigidity?

I’m also curious how the X-50 rigidity compares to the X-35 with the 3rd rail @onefinitycnc