Yeah, how'd Khamis get his name on something I built and used over a year ago?
I had some PVC collectors modeled after the simple brake ducts used on F1 cars (a simple 90 deg bend that peeks out from behind the wheel into the air stream under the car). The problem was it needed to be attached to the steering control arms, and at speed they'd vibrate a bit and translate the shaking to the steering wheel. It was annoying. I ran one session at RFR with them, then pulled 'em off.
Perhaps if they were attached to the control arm instead of the steering rods, the vibration wouldn't be noticeable, but then there's a routing issue with getting the air to the center of the rotor when the wheel turns. Though, I didn't have any of those fancy RaceComp brackets to work with.