It's a really cool gadget. I haven't had a whole lot of time to mess with it, but it's a good feeling to visually see that all my hard work in aero mods have paid off some! I already knew they did upon fillups, but it's cool to see it live. I put it in my wife's '97 Grand Am GT. It's tough to say since it's so cold, but I am getting 6-12 more mpg gallon depending on speed. I'm pleased
