I recently purchased a new 2004 Mazda RX-8 with the Grand Touring
Package, containing an in-dash GPS system.  The GPS reads its data off
of DVDs (the reader is in the back of the car).  However, the system
is currently restricted to reading only the GPS data DVDs, and will
not play commercial region 1 (or any region) discs.

I would like to avoid, if possible, connecting a different DVD player
to the screen.  That is, I would like to modify the existing reader in
some way to allow it to play commercial DVDs.  If, however, this is
not possible, I would consider adding an additional box.

In order for an answer to be considered adequate, it must provide
information on how to make the in dash screen play movies.  I am NOT
interested in installing additional screens in the seats or vanity
mirrors.  Additionally, I want my GPS to continue working.  That is, I
don?t want to replace the GPS reader with a DVD player.  I need to be
able to switch between them.  An answer will be considered outstanding
if it provides information on how to make this screen play movies
using only the hardware that came with the car.  As I said, I would
prefer not to have to add an additional reader.

It is illegal in some states to play a movie while driving, and I do
not intend to break the law.  I want my car to be as safe as possible.
 Most car entertainment systems have a feature that prevents a movie
from being played while the car is in gear.  I would like to implement
this safety feature, and a tip will be awarded if this information is
included in the answer.

Thanks for your help, and feel free to let me know if you have any
questions or need any additional information.