Some people have a lot of theoretical talk pro or con, but there's nothing like the voice of experience. Can't argue with what you feel behind the wheel. Thanks for this video!
The originals are still sold directly from the company's website. I used to drive tractor trailers and they do make a big difference, as you said, with handling and a bit with fuel economy. I have them on the top and both sides of my 6x12 enclosed motorcycle hauler and am very pleased with them. :)
Vortex Generators use the same effect that golf-ball dimples use, except on a golf-ball we don't know where the front and back is because the ball is spinning, so we cover the entire ball, whereas on a car or plane we do indeed know where the front and back is, so we only place them strategically instead of covering the entire thing.
It's good fortune that it improved your mileage. The decrease in dirt accumulation at the vehicle's rear *suggests* less turbulant of a wake. I don't think all applications should expect to measure an increase in fuel-efficiency, but I think most vehicles that have to wrestle with crosswinds seem to benefit from VGs in terms of stability. Most rules of thumb you hear about car aerodynamics ignore vehicle length and side surface area, but the wind is hardly ever 0* yaw.
