To all who have posted about the noise when its cold, from about 30 to 50 MPH, etc. There is a service campaign for this that includes the counterweights and a rear propshaft (driveshaft) replacement. The Lap joint is causing the noise. The Jaguar Service bulletin number is XT205-01. If you need a copy of my service order to show to your dealer, let me know and I will send one via e-mail in PDF format. Many thanks to Harper Jaguar in Knoxville, TN!