Cold air intake for the 1st gen RX-7 typically run up against the rule that requires you to draw your air from the original location. In the RX-7s case, that's the engine compartment.
Read the rule very carefully before you proceed further.
Additionally, yuo are not allowed do anything that isn't specifically authorized by the rules. I see lots of hacked up radiator mounting panels with tubes attached in impound on different IT cars, and they are all absolutely not legal. Nobody protests these guys, typically, because they are getting lapped in the race, but, it's a big obvious cheat.
A recent protest was done on this subject, and it went up the ladder to the appeals board, IIRC. The car owners/builders claimed that in their car, the air intake traveled out of the engine compartment, then back into the engine compartment. The opening that the air entered was located in the engine compartment. The parts outside were resonators, and there was a small hole (1/8") located at the bottom of the resonator, which the builder claimed was the "Origin" of the intake air. (It was felt that it was a condensation drain by others) The builder used that logic as the basis for locating their entire intake outside the engine compartment. The protester and the appeals board thought otherwise, and the design was pronounced illegal..
