Hi gja1404! I am fairly certain that disconnecting the speedometer at the transmission is going to be by far the easier way to go. I would work on that end. As for specifics, try your local library and see if they have the Chilton's for your 911. If not you may want to drop a dime to the parts guy or service manager at a local dealer to see if they will let you pick their brains a bit. If you have a local dealer, a fresh hot cup of coffee goes a long way! Good luck!