Driving to work this morning and the car came to a halt. I had run out of petrol. Now... as the warning light never came on, I never knew how low I was on fuel. Anyhow, the AA managed to sort me out and I was on my way. However, I've now noticed a tinny sound and I'm 99% sure I've fcuked the cat up as it sounds like the baffles. Is this common to fcuk up as a result of running out of fuel? Any ideas on how much a replacement cat is?