To make a long story short, see your local avionics shop for guidance. Each
FSDO is forming their own opinion on the Air Gizmos panel mounting
requirements and these opinions should be well-known to the avionics shops
of their respective jurisdictions.

This is quite true. We've got our 496 panel docked, and one avionics
shop (in Illinois) said we needed a 337 and a whole gob of paperwork
to install it.

Our other shop (located in Iowa) said all we needed was a signoff,
which they happily (and cheaply) did.

Different FSDOs apparently have different opinions, which means
different shops will charge HUGELY different amounts for the AirGizmo
installation. Shop around.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"