If you REally want to know more about these, PLEASE PM me, I actually have installed Professional units on many cars, and can show you how. I worked with a company called Green Future Technologies.
I know about these Units IN AND OUT.
EDIT:
They Do Work.
TRUST ME.
Double Edit:
When we installed these units we gGAuranteed 20% better gas mileage, however most of our customers were getting around 35%.
Installed on
Toyota Tacoma 2008
2008 Acura MDX
Toyota Prius
Ford F450 Diesel
MB 300E
MB 300D
Off the top of my head.
You can call A1 imports autoworks for more info.