All good advice, do check your local laws, one thing that has not been gone over yet, is whether you will only carry it in the vehicle. A car gun has a few advantages, it can be heavy, hold lots of bullets and not necessarily be concealable on the person. It can already have a laser or light attached as it does not have to be in a holster.
2) Where will it be stowed? Glove box, center console, hopefully not under the front seat, custom pistol holder under the dash or elsewhere?
3) Who else will have access to the vehicle, may determine if it needs to be in a locked container, clients, children etc... that's not that bad, as you can unlock it when your in the vehicle and lock it when others use it or when your away.
My truck has a nice big center armrest you could put an UZI in, but instead has a full size ( except for the grip reduction ) .45 glock with 2 spare magazines.
Good luck M25