There's very little you can do today to cars because the entire exhaust system is part of the emissions system which is carefully monitored by the Engine Computer.
The goal of the air intake system is to warm the fuel so it vaporizes and burns better for improved performance and emissions. Liquid fuel does not burn. It just goes out the tail pipe, wasted, and produces no power. That's why cars with carburetors years ago had chokes. It was to dump lots of fuel into the engine in hopes a big enough percentage would vaporize and burn to keep the engine running.
The idea behind cold air systems is the air will be more dense so you can pack more into each cylinder. What about the fuel needed to go with it? If the system tricks the intake air temperature sensor into thinking the air is colder, the computer will add more fuel to go with it. That means you'll be pressing the gas pedal a little less to achieve the same speed. What you might gain is a little higher top speed but unless you're running wide-open-throttle constantly on the racetrack, what good is that? You can already reach red line. Do you want to go faster?
Intercoolers are used quite often on turbocharged vehicles because compressing the air heats it up. Too much heat is not a good thing either as it will make the engine run hotter leading to spark knock. The vaporizing fuel gets cold when it expands as it leaves the injector and that helps cool the intake valve.