[UFO]

I'll answer that too then, since no one else is jumping to defend. They don't work, and that's why they aren't standard issue.

There is no A-B data shown, of course. The "guarantee" is subject to restocking fees, ludicrous as they should not be selling used units. They also will charge for "repairs" on returned systems, so my guess is they will not be issuing very much of your original purchase.

Bottom line, you could buy one and document no mpg gains, return it under the "guarantee" and they will still make money, and you will still lose money Forget about any class action stuff about false advertising, as they would surely make the claim the users did not install the units correctly.