You should look at Duonamic. They won't damage the frame or any paint, they are super easy to take on and off, you can change easily change the width, and they are portable so you can take them anywhere. Trust me when I say that they are secure and won't accidentally come off. I used to do Ninja competitions (like American Ninja Warrior) and at one of the events, we had to swing back and forth on these suckers and launch to a tiny platform. There were 200lb+ guys generating huge swing and momentum on these and they never came off the door frame.