Sorry Andy, only re-reading your post now I noticed this
We noticed that with the existing setup the rubber mounts were under tension so they added 10mm to the length of the o/s pipe so that the rubbers get an easier life.
Can you explain this a bit more clearly to a non-native English speaker, please? What is the o/s pipe and where exactly were the 10 mm added?
Sorry - In the UK, the offside (o/s) is the right side of the car (when viewed from inside the car looking out over the bonnet). The nearside (n/s) is the left of the car - the side nearest the kerb here in the UK. English lesson over!
When they cut a section out of the pipe for the new flex joint they cut out 10mm less than the actual length of the flex section. Once welded together, this had the effect of making the overall length of the exhaust 10mm longer. This allows it to have a decent overlap onto the header pipe whilst ensuring that the exhaust rubber mounts are not under any longitudinal tension. The o/s pipe was just a little too short before. The length of the n/s pipe was fine by the way. I expect this all varies from car to car!
