Electronic Speedometer calibration

you don't

you take it to the dealer, and if.......IF..........the tire size that you put on is within the limits of the ECM programming, it can be 're-flashed' to make the speedo read correctly

you could also get one of the superchips micro tuners, they allow you to set the tire size. Plus they are a code scanner, plus they supposedly give better shift patterns and a little bit of power.

Never used one myself, but I hear they do a nice job on the shift points.

l8r Jeff