Thanks for the added information...just to clarifiy, I have never had any dealings with Coastal Tech...I simply researched for options to be able to play the DVD player while driving, and they were the only aftermarket supplier I could find. I cannot speak to their customer service, but it sounds like your warning is sage advice.
Back then, I decided against the expense. At one time, it definitely would have been helpful with the kids, as PecosRiver suggested. It is always a personal choice with stuff like this, and I have no issue with someone deciding for or against the device. My personal concern was that it could be a distraction (part of an age-old debate).
To be honest, I wanted a MyGig (added it myself) because I was interested in both the GPS and MP3 capabilities. I don't think I've ever used the DVD player, except to update the unit. I absolutely love the navigation, and the music player is OK (though library management is a pain...at least on mine).
Anyway, good luck with a solution, CrazyKid! I hope this information has been helpful!