I did buy the kit. Just waiting for the opportunity to install it.
My existing garage is piled high with boxes, hardware, and fixtures. There's nowhere to work, comfortably, and it's too "mizzable" to work outside, if I don't have to.
They have finally set the poles for my shop, but I will be fortunate if it's completed by the end of the year (unless they surprise me.)
Edit - I have the tray in both of my cars. It just sits there. Not fastened in. It even holds my phone in place.