Hi I got my cobra sport exhaust delivered today for my cooper s r56. It came with 2 exhaust clamps and 2 steel 63mm o rings. Does anyone know if this is all I need to change the exhaust or should I replace the turbo to down pipe gasket and the clamp from the bottom of down pipe to centre section. Was not sure what the steel o rings are for as I have never came accross them with any other exhausts I have bought. Thanks for any info.