I would plan on hanging the carpet for a few days. It can be a pain getting all the wrinkles out of it that happen in shipping and storage.
Any areas that need cut out, like the metal plate for the shifter and the studs for the seats, just make an "X" in the carpet over the top of them. Don't try and cut a hole, if it has to be adjusted and won't line up anymore you won't have trouble hiding the mistake.