I've stumbled across a few horror stories about peoples attempts at coding. Someone changed their start up screen to say Quattro and it messed up their fuel gauge from working! Apparently the Quattro models have two fuel tanks instead of one on non-quarto cars. It didn't just change the start up screen. It made the entire car think it was Quattro. Not only that but apparently the car now also thought it was left hand drive!
I'd be wary of any coding and would feel a lot happier finding a professional for retrofit coding work. Although there is no way to know if they are doing it properly either. Just be very careful and most importantly, whatever you are using, backup your existing code values or write them down in case it goes wrong and you need to revert.
I'm looking at getting the reverse camera and folding mirrors for mine too but I would like to take it to a shop who can do it all for me. If anyone has any recommendations for the South East of where I can get that done I'm all ears!