I just put together a SpeedoCorrector kit, though I've yet to install it on my bike. I still have to test it, but it would appear to work with pretty much any electronic speedo. I found a source for the PC boards, and if I source the electronic parts and program the microcontroller myself, I think I can offer these things for about $65, assembled, tested and delivered.

I never installed a SpeedoHealer on my ZX14, so I'm not sure what they run, or how friendly the programming is. The this kit is adjustable in 1% increments, from 1-99%.

Whaddya think?

-Matt

The SpeedoHealer is water resistant, shockproof (up to a point - grin), and comes with all connections.

I bought my Speedohealer from them directly for $75 shipped last summer.