I run on a rough track all the time but relative to other buggies, you hardly notice the rough terrain in the Tekno.

Spares, nothing breaks regularly but for wear maybe buy yourself an aluminum servo steering horn just to be safe otherwise no hop ups needed off the bat but to have as back up for wear, clutch shoes obviously, brake pads, and maybe some rear diff outdrives. Those are all for normal wear, as for spares for stuff that breaks, there's not much that breaks. The only things that you may need if you don't run the rear braces correctly are a rear center drive shaft and rear diff case, the shaft will bend and case break if not used right. I have a whole box of parts and never use it haha.