They both work off the same signal. My speedo is almost dead on, and my odo reads 1 mile slow for every 100 (gps verified), so you'll be reading 10 miles low for every 1000, 100 miles for every 10,000, and 500 for every 50,000. For having an accurate speedo I don't think thats too bad at all
So when your bike hits 100k on the odo you've actually got 101k.....a non issue imo
and doesn't hurt resale value any either
The new V4 speedohealer is awesome...SUPER easy to set (unlike the old one) and has the ability to switch between 2 settings on the fly, so you can bypass the speed restriction on kawi bikes like the 14 which are controlled by the speedometer readings....and not rpms like the busa