My dealer did the full swap on a Carrera S in 4 hours with a good tech. I arrived at 7:30, drove out at 11:30. Full PSE with button install and programming. I've heard others say 5-6 hours. 12 is nuts. Call around and get multiple quotes. Also, see if any of your local dealers have a system in stock and on sale.

 

i got lucky and my car has this option. a 'must have' option