Also on another note, Before they fitted the new exhaust they should have realised that the new one looked nothing like the original, therefore they should not have fitted it, thus they have fitted an inadequate exhaust and not for the car. They have to replace with a new one to the exact same spec as the original. Secondly when the new exhaust and cat has been fitted the car needs to be idleing for approx 15 mins to allow the cat to reach temperature which is approx 350 degrees to 450 degrees this is a must otherwise the cats will eventually break down and become useless. This has to happen every time you start the car.
I know this may sound boring BUT if you require your cats to work properly and efficiantly then this must be done. Also it may be best to replace the lambda probes at the same time as these breakdown over time. For stop start driving these need to be replaced at about 30,000 to 45,000 miles. Motorway driving anything between 60,000 and 80,000. I have done the training on these so its not just guess work.
After this little info for all of you I would stick to your guns get the exhaust replaced WITH the correct pipe, wether its pattern or genuine, from the exhaust fitter's and pay no more money. There mistake, there problem to rectify at there cost.
Paul
