The 865 may not get the amount of performance improvement the 790 does by adding BB kit because of the different cams, but all the models get performance improvements from increasing the air flow in and out along with proper jetting. Adding the Specialty Spares, removing AI and snorkel, and re-jetting along with the UNI made a major performance difference in my stock bike. Other than the cost of the pipes, it's all cheap and very easy with no detailed mods. A stock 865 does perform better than a stock 790. With basic mods, it still will perform slightly better. I'm all for more torque which was the main reason I did the BB mod.
