Yeah that's the way to go if your welding it back together and repainting. I was trying to limit the welding on my car due to not having a welder yet. I've just been borrowing one until I can find a sweet deal on a Miller.Cut an opening around the spot welds and slide the crash bar out the side, then weld it closed.
Much less work than trying to cut the bar into pieces inside the door.
If the car is driven on the street at all, I would leave the front bars in place and only remove the rear...