I think most of the people who have forked over the $999 for the Wagner unit were either looking for the added HP or solution to the OEM moisture problem. I'm not real sure that there would be any noticeable MPG to be seen, even the Wagner website says "saves gas". But, does not go so far as to state a measured savings. Just as it says "helps to prevent the common "condensation Issue" ", but does not go so far as to state it is a "Fix". Which I feel is a safe way to advertise a product.
Even if the intercooler did provide a 1.5 to 2 MPG increase it would take a lot of fuel to make it pay for itself as only an economy aftermarket item. Now, it you are going to tow with your Ecoboost quit a bit the added designed abilities of the Wagner under these conditions would pay for itself in the added towing benefits.
I have always been of the train of thought, that the best thing you can do to improve your MPG is proper control of your "Go Fast Foot". Apply pressure to your gas pedal as though there is a raw egg under it and you don't want to break that egg.
I have heard from a number of people who have installed the SCT 87 Octane performance program and have seen MPG gains of 1 to 2 MPG when driven in a normal driving manner. It may have to do with the chance in shift points of the transmission or power curve. Price $379.
All that above being said, if I have to replace my intercooler at any point in the future or if that condensation problem should show up with my truck. I'll purchase the Wagner unit as a replacement without giving it a second thought do to all the benefits it offers. One of which would not be for increase in mileage gains.
I agree with all you've said, but when I'm considering buying something that costs that much I'd like to know as much about it as possible, both the good and the bad. I contacted Wagner and he said he'd gotten a 1 - 2 mpg increase towing a trailer but I was hoping to find some "real use" people to see what they had gotten.
We get that question alot, will it make the truck more fuel efficient yes. Now it is not something that us nor Wagner have ever tried to quantify. The benefits of the intercooler far surpass its fuel mileage savings. The towing benefits and the HP benefits speak for themselves. Anytime you add power to a car/truck it has more power to do work with. The more power the easier the work, the less fuel is needed. So under "normal" driving conditions fuel mileage will improve with anything that makes more power. Even when we do supercharger kits where we upgrade fuel pump and fuel injectors we pick up fuel mileage if driven regularly. Now if you constatly step on it, then the effect works in the opposite the direction.