I also cut mine out after the car was painted and lettered. I drilled out the spot welds and cut the bars in pieces to remove. After the spot welds were drilled, I slid a thin piece of aluminum between the bar and the door skin, to protect the paint and lettering. Some times you will find some spots of adhesive (1" dollops) between the skin and beam, cut these with a thin wire.
Take your time and you will be OK. I found it easier to remove the door to do this. Your door hinges will thank you.
Brian Dunnigan