Both are scams. 

It's a fake, if anything, this will damage your economy and increases your engine's risk of getting metal bits in it when it falls apart.

This is a perfect example of the term "snake oil"

They're scams meant to separate you from your $$. 

Fake garbage. 

If only it were that simple.  Automakers spend so much time and money to meet ever stringent CAFE standards while at the same time trying to give the consumer some performance that if this product truly worked it already would have been engineered into the majority of vehicles being sold today.  But that’s just not the case.  This is another product in the long line of products that are too good to be true and are simply scams.

Please don't waste your money on those scams. They will create more negatives than positives.

As someone who has tested products like that to an extreme extent on a dyno, I can confidently say they are junk.