Come on now it not like this is uncommon for high ticket items, car dealers for example. The managers drive the latest model (at very little cost to them) then sell them the car at discount a months later. Even on the other spectrum like the food industry, I know people who can have 1 free meal a day from the place they work at. Also think about it, this is probably the best advertising electronics companies could get. Would you buy a car if you only got to look at a model, well how do you test drive a navi system? You let an installer show you his ride. I would bet that helps move units more then anything.
I would guess 400 is probably around cost or below for the parts alone but for new technology ~25% is normal. When you buy technology you are paying for R/D, technical staff salaries, retooling, documentation, etc. As time goes on this things get paid for and costs lower but so does demand. And don't forget overhead; things like storage, paying employees, shipping and keeping the lights on.