Alright, I have put a few weeks and 6k miles on my Evolution, and I am impressed enough to share what a good job Daimler trucks has done on this setup. I always thought it was just an aero package, but it is a lot more than that. 1. Aero. Yes, a lot of extra fairings and wind splitters and stuff are definitely here. It seems to make a big difference in windy conditions, and keeps the truck quieter to boot. 2. DD15 engine. This is a big ol engine, 14.8l, and it's a bit counter-intuitive that upsizing the engine would be the best option. But it works. It apparently was designed with this application in mind. 505hp and 1650tq are not class-leading for this size of engine. But it is far less boosty, and accommodates taller gearing (<1300rpm@60). It's also a lot more flexible in terms of being left in a taller gear, and probably accounts for the truck's virtual immunity to load weight and partly its resilience in hilly terrain. 3. Adaptive cruise control. I hated the radar cruise control in my first truck: too sensitive and abrupt, it was downright dangerous. It has, well, evolved. It has been smoothed out a lot and now incorporates terrain-sensing capabilities. It'll speed up 4mph and spool the turbo for coming uphills, and coast down 4mph to anticipate downhills. It essentially is hypermiling-lite. And it WORKS with far more patience and exactitude than I could give for 8+hr per day. 4. Upgraded secondary IP display. It now has a real-time MPG bar, which is great for stop-and-go or general urban driving. Anecdotally I'd say it's good for 10-20% savings in those situations. It also has digital readout a for boost pressure and oil temperature, also useful in certain situations. Altogether, I tracked the first 3100 miles and came up with an 8.36mpg average, with many more 9- or 10-plus mpg stretches than ever. Any given week I used to average mid-7s to mid-8s. Now, this setup seems to consolidate the averages right towards the upper end of that range, really cleaning out the number of dud days, minimizing external factors such as wind, and still eking out a little extra on the good days. And that's not even counting some of the other details which have been improved too. Really liking this truck!