Comparing a 1998 TDI to a 2003 really skews the maintanance cost; but time will equalize them eventually.
Odometer Life MPG Fuel Cost Maintenance Cost Total Cost/Mile
Jetta TDI 181992 42.88 $0.034 $0.022 $0.056
Passat 1.8T 21798 25.91 $0.071 $0.005 $0.076