most likely would need the subframe reinforcement. I'm 5 10" and I've a hard time wrestling the XR6 seeing how it's like a tall as a tower. Offroad it's been a great ride but once it's loaded up with stuff it's just another heavy pig (+ subframe failure possibility).
I had quite a mixed experience with getting mods for it as well. Needed to custom the pannier rack and rear rack with a welder. That aside, it is a wonderful ride when it's on the move, quick off the line, not too bad with highways, feels great offroad (unless you drop it, then it hates starting when hot).