Sorry for not posting it on the technical but I need a quick response. I got the Crawford cats and 3/8 spacer installed today. The cat metal covers were already bent when I got them but one of them is still rattling. I have to drive 400 miles tommorow and will probably not make it to adjust the cat before I go.
Q: Can I damage the cat by driving with it rattling? It rattles only under mid to heavy acceleration.

I had the same problem and drove like that for a week. Then while my car was on the lift for an oil change, the tech just moved the car a little to make more space between the heatshield and the frame, took 15 seconds, problem gone. I don't think it will be that big a deal if you leave it as is for now, it's the heatshield vibrating against the floor, not the cat itself.

Thanks Finiti, that's a relief.