There's a possibility that it could be a problem. The engine in the 2.2 Vectra moves a massive amount for some reason? The flexi is at the front of the pipe to help fatigue on the pipe assembly when the engine moves back and forth under load. If the flexi is behind the cat, it would mean that all of the stress is being put into the cat.
Its possible that you may have a crack in the weld. My thought has always been that the Vectra should have had 2 flexi pipes. The 1st one just after the manifold joint and the second as it is now, just after the bend.
