Lets see- yes, I kept the touch overlay.
the material around the screen is accrylic. It has properties very similar to plexi. The acrylic is very thin, so it keeps the screen fairly flush.
The Accrylic is cut in the shape of the lcd,
(with a hole in the center) so it fits over the touch "glass plate"
Yup, Ill be at the track this weekend
The extra controls are nice - I think you mean the keypad and mouse -
For precision movements - (like my lousy GPS software, ) the mouse is great to click a tiny street or road.
If you are refering to the buttons for the LCD - the original buttons are still there (just under the dash) I didnt chop up the circuit board. I just soldered on extra wires, and ran another set of buttons for various LCD adjustments around to the other side of the dash. And yes, I use them. (turn down the contrast at night)