I installed the factory unit in my '98, after disconnecting the battery, wait about an hour for the capacitor that energizes the airbags to discharge - I believe from memory that the reason a capacitor stores the b+ is because sometimes in an accident the battery is destroyed before the airbag has a chance to deploy. I could be wrong, but I remember the instructions said to wait.
A good idea that after everything is reconnected, reach in from the passenger side to start the vehicle. I also vaguely remember that the airbag/cover should be placed gently downward on the cover side on a bench, if it pops, it'll cause less damage that way.
This was five years ago, anyone else feel free to refresh my memory if this sounds inaccurate.
Mike/NY #300