it will never make you gain HP
what the hood those is free up weight first of all
second it provides air flow to engine with raised hood scoop which lets the engine run cooler and free up the stress on your engine, lettin it perform better
third would be even more air flow with the second vent that faces backwards which was designed to let the hot air out from the engine. it basicly circulated from the first hood scoop and out the second
hope this helps