The XR is a cool bike. I'm not sure if you are looking at the bike for ideas for your ninja, or thinking about dualsporting the XR.
There are some drawbacks to dualsporting the XR. The motor is race breed and the oil change intervals are at 1000 miles. The rear subframe is weak and isn't made for hauling cases or gear. The tires are sized more for off road work than highway. I went up one tooth in the front, but you were still holding the RPM up high to go 80 on the interstate. It only has a kickstarter. If you want a more dirtworthy machine than a KLR or a 640Adv, the XR would be a good platform.