Note to other forum members: I pruchased the SpeedoHealer from Cal-Sportbike, and couldn't be happier (other than I paid full retail!). The kit is truly plug & play - very easy to install & program. SpeedoHealer provides an on-line calculator that takes the guess work out of programming. Very nice.
I looked at both the SpeedoHealer and YellowBox, and I think the SpeedoHealer beats it hands down. Wider adjustment range, on-the-fly unit conversion (mph to kph, or vice versa,. just pull over and make the change - granted not important on a ZX-10R because it can do this as well), independent dedicated logical units for calibration & unit conversion, ODO optimization mode, SmartTRIP for better ODO accuracy over time, top speed recall, etc. It truly has it all.
I was also very happy with my limited experience with Cal-Sportbike. The unit was shipped and at my door within my expected time frame. If they are offering a discount, and you have considered something like this, DO IT!
Xusia, H.S.B.E. (High Speed Bug Exterminator)