A buddy of mine did a slick trick with his deck.
He cut the panel out of a non GT dash and installed the deck behind the panel inside the dash. He re-mounted the panel on spring loaded hinges with a catch pin.
The dash looks totally solid and uncut with a junk old 2 post radio in the dash.
But when you pull the little (Hair size) catch pin....the panel/door opens up to reveal the deck.
It is very quite cool!
Sorry, no photos allowed