Boss Performance Chips? Anybody try one?

[Robb31]

Ive been looking on ebay and the adds that say 300 horsepower/ 85 mpg attract your eye. That's obviously bull though. For a product that costs $30. I was wondering if anybody has tried them and if they have noticed any more horsepower or fuel economy.

[Rigger]

Dont bother with the cheap chips and instead buy a race ECU or a piggy back race ECU that can be ajusted for when or if you do more mods to your engine. Also the piggy back systems can be switched off and revert back to standard with a flick of a switch.
I guess these things are avalable in the USA.