Snake oil... ... I don't think so. Yes they are a little high, but what isn't these days. I never bought one for the increased power of mileage, I real don't care about either one, I bought one to see if it would help eliminate the drone associated with the larger free flowing exhaust systems. They have a different way of looking at the problem, their thinking is most definitely "Out of the Box", and I find it refreshing.
I installed the Aero Turbine muffler 18" in front of my Hog Performance muffler, it was very easy, just cut out a section and refit the new muffler into place. The first thing you will notice is the exhaust note is much different, sound levels are lower and the exhaust has a "Whooshing" sound to it, a little like a leek in a high pressure air line. For me, the best part came on the road and while towing, the awe full drone was reduced in both sound level and in RPM range. With some additional work in insulating both cab and exhaust system, I have gotten the interior sound levels down to exceptional levels. Radio's can be heard and conversations can take place at normal levels, I simply love the way my insulating efforts have turned out, way past what I thought was possible. And yes the Aero turbine muffler was apart of that effort. For me the 220. 00 bucks was money well spent, it did what I wanted it to do.