Hondata have developed a special high temperature insulating gasket which replaces the stock intake gasket. This significantly reduces the transfer of heat from the head to the intake and incoming air giving you up to 5% more power.
Turbocharged cars often use an aluminum intercooler to cool the air compressed by the turbo. The intake manifold is also made of aluminum but because it is heated by the head from combustion and coolant, works in reverse to an intercooler by heating the intake air by as much as 50° C.
Around town, testing has shown an average drop of around 10 degrees C which is good for around 3 percent power increase. Remember though that 3 percent power increase is difficult to feel. You'd feel a greater change in performance getting rid of that passenger. In certain conditions a 30° C drop has been measured.