I recently installed the Vararam Air Grabber and the Bully Dog Hemi Plus with the regular tune and have noticed a pretty good difference in fuel consumption! I am running 35x12.5 Toyo OC MT's and was getting between 16.5-17.5 L/100km and now I am getting 13.5-14 L/100km on the highway. I haven't changed the way that I drive at all either, I keep it at around 110 km/h. I am also running a Mufflex DOD14. Last year at this time, before installing any of this stuff I was getting between 18-20 L/100km... I am pretty impressed with the difference it has made! I would recommend any of these mods!
I do notice that it has more get up and go as well! Not the gains that they say you could get I'm sure, but noticeable for sure! Much better throttle response!