(Only one needed per engine, this replaces the factory gasket between the head and the lower intake runners. For the non-turbo 2JZ-GE cylinder head.)
Typical results with a heat shielding gasket would be a 17-20 degree (F) drop in intake plenum temp, and a 8-10 degree (F)drop in intake air temp. The lower gasket is going to make the most dramatic change in intake air temperature, but the upper gasket makes it work even better!