Hey. For your boost gauge, use a dremel and sand out the hole thats already there a little bit bigger. That will allow your boost gauge to sit down inside the tray and the lid will close. Then you can take the gauge out, put the ashtray back in and it looks stock for when you sell.
I have the same gauge but my lid closes. Dont make the hole too big. Just make it big enough for the gauge to sit halfway down with the sides of the gauge still touching the ashtray. That holds the gauge in place and allows the lid to close.