They are starting to use notebook hard drives in MP3 devices in car radios. So, the right notebook hard drives can be used in vehicles for normal use.

IBM notebooks have a protocol that parks the hard drive if it detects a falling notebook or other harsh movement.

With that said, you should just get on the list for the upcoming Lexus RX330h (hybrid) which will have more horsepower than a non-hybrid RX330 (270hp) and which has a navigation screen mounted where it should be (in the console and a suitable size and viewing angle) without distracting the driver or promoting accidents.

Note that Lexus has pushed back the introduction of this vehicle until December to insure some stock as there have already been over 20,000 pre-orders for this vehicle.