Drove a new 50i (see fraser Im teachable) 340 miles highway...averaged around 80MPH....computer showed 17 MPG at the end....I think the gearbox helps a little.....These were the first miles on this car so Im guessing it may improve a little...for me the pure joy of the new engine outweighs the fuel cost (im coming out of a 2007 x-5 3.0)...but then I'm in the US and fuel and cars are way cheaper here...