Whilst I can agree in there being no such thing as cheap horsepower at the end of the day we don't all have the big bucks so I think it a fair exercise the investigate cheap mods that can add some small gain..after all, lots of small gains add up. The claim in the ad that it adds 20hp is bogus though. I have done this mod on my car (I went for the 0.20c option from ***** Smith). It definitely added some responsiveness and noticeable power increase but I would guess somewhere closer to 2-5 hp. I've had it running now for 18months with no adverse side affects or dramatically increased fuel consumption. I must try the garlic sauce though LOL.