I wanted to know if there would be any adverse affects to mounting the Grom Audio box behind the ashtray/cig lighter console on top of the tunnel, using some adhesive strips. Or is there a better place to mount it outside of the glovebox?

 

That area is hot so using an adhesive to attach the box might not hold longer.
Mine is inside the glovebox attached with double sided tape and its not holding good either.
I dont bother fixing it.

 

I tie wrapped mine above the accelerator. Been there a few years, no issues...

 

I stuck the box to the back of the glovebox.

 

I don't have a navigation unit in mine so I taped it under the dash on the top part of the center air vents. I used double sided tape (use the 3M brand heavy duty double sided velcro) and its been holding strong for about a year now. I develop a rattle from the wires rubbing against the top of the dash which I fixed by ziptying the wires to various parts of the dash. Good luck on your install.

 

All these rattling and adhesive problems would be fixed, if you mounted it using 2 zip ties to the metal bracket behind the glove box compartment. It already has 2 notches that will lock the zipties in, preventing sideways slippage.