I've removed the nav/radio about 4 times, nothing snapped on my sofar. Only thing that came loose were the small metal clips attaching the fascia surround, these can easiliy be glued back on. I would advise care when putting the center exhaust piece back in, there are a few small tabs which have to be inserted right or it will not fit, and using force at that point will snap these tabs.
If it's cold outside, i do drive around for a few minuts with heater on hi and all the air exhausting trough the center vents to get the plastic more flexible.
Just don't be afraid to use a bit of force...