Came off the motorway tonight and the exhaust was making a terrible racket. The exhaust is only 3 years old, Milltek, and the garage said the CAT's were rattling badly but still OK at the last MOT and the noise seems to be coming from the front of the car as far as I can tell. When I got home I did jack the car up to see if it was an obvious problem, but when I fired the old girl up the noise didn't seem anywhere near as bad and I couldn't see anything obviously wrong, the CAT's looked in surprisingly good nick for 13 years old and 180k. Any pointers? Looking around it looks like replacements are around £130 each.