It's a cheap resistor; the same garbage you see all the time on eBay. What it does is trick your ECU into thinking the air coming into the engine is cooler than it really is so the ECu will advance the timing more and increase the amount of fuel going to the injectors. You would almost surely need to run premium fuel so you don't get premature ignition of the fuel.air mixture, and your fuel mileage might suffer on top of that. Fact of the matter is you can get the same result by just advancing your base timing setting a couple degrees, but you'll still probably need premium fuel. Oh, and at best, whther you use the resistor or set the timing manually, you are looking at maybe 5 HP max, and that's probably wishful thinking.