Apparently, it's possible to get 200+ mpg without HHO, fuel line magnets, super carburators, fuel pills, acetone, hydroxy boost, hydrogen, fuel atomizer.catalyst -- you name it. All it takes a light weight, aerodynamic car with a very efficient Diesel hybrid engine.
First drive: 261 mpg Volkswagen XL1
"this diesel plug-in hybrid recently received a mind-boggling rating from European authorities of 261 mpg, far and away a record"

 

that is interesting, i've wondered why we don't see diesel hybrids. it works great for trains. why not size it down. hopefully another manufacturer will take note and something truly amazing will go mainstream.