Used search now and also before. Have changed the rear box because corrosione holes and lately also the middle box. I know that the cats are normaly the issue of rattle or heat shield. I have checked all of shield under the car and one needed to be fixed better. After reading the old topics am not sure that the cats are the reason of rattle. On the idle there is no rattling sound at all and also when going steady speed. When I hit the throttle the noise is there- metallic rattle. If I push harder and gearbox changes down 2 gears or more the sound of engine becomes louder than rattling.