Happened to notice the recent date on your post and thought I would help out. You may have noticed the forums here are not heavily used, but at times are helpful. You will be fine on your Niner hardtail 29er. It can handle any course out there, from non-technical to rocky like the old Maui course, or the new one as well. XTERRA bike courses are hard to categorize because there are so many site-specific variables, but I would suggest picturing a typical mtb XC course at high speeds. I have used a Niner hardtail for many Xterra races for the last 6 years, scandium Air 9 and now carbon. Tubeless and low pressure helps a lot. Now, if money is not a concern you probably know you can now get a 29er carbon dualie which will weigh the same or less than your hardtail with 80-100 mm XC race travel. That could be better for a one quiver race bike, but be prepared to spend lots of $$$. I would save the money for upgrades to your hardtail like race wheelsets, etc.