planning to take family to LEGOLAND, its a 2K round trip mostly at cali speeds of 78-80MPH the entire way. since Oregon still has a snail pace 55mph speed limit I really do not know how well our TDI's do at higher speeds in regards to MPG? What can I expect at these higher speeds? 2013 with a DSG? Reason I ask is because I just bought the wifey a Highlander Hybrid that manages 25MPG highway and it has more room for her junk but drives like a shopping cart full of bowling balls