Stunt 101 - We have been running the 29 since its introduction, I sponsor 4 riders and we have had really great results racing these bikes with the following modifications - Upgrade to pro taper bars, change out stock grips,add uni air filter, upgrade plastic to klx110/kx65 ( minor modifications required ) upgrade rear axle, upgrade tires ( michelin starcross ) upgrade chain ( rk 420 ), upgrade seat foam and cover ( factory fx ), upgrade rear sprocket ( depending on track ) dis-assemble rear swingarm and steering stem and re-grease bearings, remove and loc-tite all bolts, run in motor with mineral based mc oil and then replace with good quality syn-blend mc oil. Then replace stock plug with ngk cr7hsa. We occasionally run VP U-4 race fuel. We run the motors in stock form, minor carb adjustments. Hope this helps.