http://www.cnn.com/2006/TECH/science...ion/index.html
confirms what many of us already thought.. lots of fuel savers tested, not a single one was found to work.. including the tornado, which was shown to actually decrease fuel economy on a navigator
my stock vx gets 17.5-18.5 in a combination of city and highway, 19 sometimes now that I put a green performance air filter in and removed the elbow into the stock airbox.. lookin to get a new muffler soon, anyone have experience with mufflers that increase fuel econ?