I had the same thing happen to me. The door seal was somewhat defective, but if I slammed the door, then water wouldn't come in. I solved the problem by taking out the carpets and pulling the drain-plugs.
You weren't born in 1993, were you? (based on your user id)
Drive it like you rented it, not like you stole it. Cus if you stole it, you'd be driving 5 mph below the speed limit and using your turn signals.