Lotus delivered the Elise S1 with mild steel downpipes. They are a well known source for troubles, specifically around the flexpiece and the manifold flange.
Snapping the flex-piece means hot exhaust fumes will exit from the flexpiece, causing power loss, a lot of noise and a mot failure.

This item has been produced from Stainless steel, the flex piece is welded in another way and is expected to last a lot longer then the original item..