I want to remove one of the air vents, and put a gauge in there, I saw it on youtube, and the poster has yet to respond after weeks. I was wondering if anyone here has a put a gauge in one of the vents, if so what gauge and size did you use?

 

This is the only one I have found VentPod Single Gauge Pod for Mazda 3 / Mazdaspeed 3 #EHP-MZ3-VP - Revolution Performance Motorsports!. Not sure if it would work in the 6, but don't see why it would not.

-Sheldon.