If you don't put mileage on a TDI regularly you will clog the DPF. Once a WEEK Highway jaunts are needed to clean that out. I never drive my TDI if it is less than a 20 Mile drive... This allows plenty of time for the system to fully warm up and any measurments of the dpf to be accurate. @ Brian@PuenteHillsVW, you should know this if you sell or work on the cars. The torque is nice, but if you are talking people who drive short commutes into TDIs, you are essentially giving them false sense of security with the new car. Warranties don't cover trouble caused by Driver Error.