The reason why intercoolers give power is because when a turbocharger or a supercharger compresses air (even when its cold), it gets hot, so defeating the cold air intake effect. so the intercooler goes between the turbocharger and the engine to re-cool the compressed air for a double boost in power.
this thread is not really for intercooler, just wanted to tell you how it works and what is does, so you do now mistake it again.
But the things you are talking about now are a ram air effect, and would only increase power if its directly connected perfectly to the carb. and if you just atach it to the body, it will just cool the engine.