When I worked for Honda I always wondered if some of those would fit on the TR7 as we had many different types, however, I never got a chance to try and fit any. I figured it would just add another place where water could accumulate and cause rust
Wouldn't help. Air goes in the front hole on side up over the inner aqnd outer fender an out the holes at bottom of front sill (ahead of door). My spider has triangular plastic pieces to help create a low pressure to help draw the air through (to help dry it out when it gets wet?) Unfortunately it would also suck in water when rainy/wet. When I had my front bumper off I liberally sprayed in waxoil and you sould see the mist come out these holes. That's where your rust comes from, not the wheel well (outside) particularly, which is open and can dry out easier.
TR7 Spider - 1978 Spifire - 1976 Spitfire - 1988 Tercel 4X4 - Kali on Integra - 1991 Integra