2 of my buddy's went to Colorado and got the fuel milage you are talking about. Both have the TM on their bike But when they came back o Texas the fuel milage wasn't the same It dropped back on the Baggers to 42-44 mpg Also V&H told me on the phone is anybody goes past exhaust and high flow air kit, to not use their unit People don't leave their bikes stock because you cn make them run o much better and keep the reliability in. But like you said, IF fuel milage is your main concern LEAVE it STOCK. Out of 100 people. how many people leave a bike stock Harley's was built to do changes nd add things to them Look at any HD catalog& go to the HD shops Everybody is doing modifications and making changes. If the stopped doing that HD would go out if business. I have put TM on my bike and friends bikes, non of them has taken the unit off their bike. I don't care how ou do it. It's your bike and your project But if you look at the long run nd you don't want to buy different parts over and over. there can be a more expensive but easier way My question is, Why buy a 20,000 motorcycle and buy a cheap tuner that really isn't a tuner. Do it right or leave it stock.