I bought a set of NACA vents from Van's and they work great. I live in the deep south. They are put in about where Phil's are. I used the cheap black plastic eyeball vents that came with them. To connect them I just bought some heater hose at NAPA that would allow a slip fit. The eyeball just butts up to the NACA inlet. No ducting at all.

I would do it again but I might spring for some better eyeballs.

YMMV