I've read about after-market units that connect through OBD-II, although I'm suspicious about the quality of those implementations and also the compatibility. The upcoming product from Navdy looks promising, but I believe that it only gets its info from a smart-phone, and not from the OBD-II...
As far as HUD is concerned, according to the owners manual, if you opt for the Adaptive Cruise Control, there's already a HUD unit installed in the car. Apparently there are messages projected on the windshield. Here's the snipit from the owner's manual:
Heads Up Display (If Equipped)
A...