I'm installing a used speedo and have the Bentley manual but it doesn't mention all of the steps for the installation process. My understanding, (after research online and talking to vw parts dealer) is after attaching the wires to the back of the speedo I'm supposed to hook up to the computer to make it recognize and calibrate the speedo. Does anyone have experience with this? Can I just plug in the new speedo without calibrating it? Do I only have one chance at calibration?