I got one kit. I'll do each cylinder by itself. My main tuning issue is the mid-range from 2500-7500 rpm, which can easily be adjusted with road testing and data collection instead of using a dyno. I already have a bung in place next to the one on the forward heads exhaust, and there is a 2nd place for a bung on the vertical cylinders exhaust, I just need to pull the pipes, grind the old O2 sensor bung down and weld the new bung in the same spot. I want to be able to use the stock O2 sensors in case I ever want to revert to a stock engine management system, like if I sell the bike to someone who is a stickler for it being 'original'