The stock nav unit was not touch screen, so you would also have to carve into the center console to mount the controls. I remember reading a write-up somebody did about adding a pop up nav unit to their ms3. They went with a touch screen unit, had to replace the top part of the dash and their headunit (nav passed through it), routed wires all over the place, and ended up paying thousands of dollars for it. The sad truth is there is no cheap or easy way to go about doing this. Best thing to do is ask yourself, "is a really tech looking nav unit in my dash worth thousands of dollars and numerous hours of my time?" If the answer is no, then you may just want to consider mounting a portable nav in that compartment (you can hide the wires so it looks clean) and call it a day.