Hi all, I had noticed for a few days a smell of exhaust fumes in the car when stopped in traffic. At first I thought it must be the car in front but gradually I realized it was my car. On inspection I have found that the 2nd Cat (under the drivers seat) which is shaped like a can has a split forming around the seam. The rest of the exhaust system appears to be in good shape with no corrosion or signs of leakage so this must be a stress fracture? Anyway I took the car to my local exhaust man and he has said it can be welded but would have to be removed from the car or could be bypassed with a piece of pipe or could be replaced at a cost of about £300 inc VAT and fitting. I am quite keen to remove the cat as I have heard this can improve performance and economy. I would however have to get a piece of pipe made to the correct diameter and shape which could be a problem. I am not against replacing the cat as the price is not anywhere near as high as I thought it would be but I would be fitting an aftermarket part which I am not sure about. Does anyone have any experience of this particular issue?