[Dukedesmo]

Both my M900 and 916 have spring connected exhausts throughout.

The M900 as it is an aftermarket setup and 916 are like that from the factory. The benefits IMO are that there is room for movement/expansion.

As an example my old Guzzi has fixed into the heads exhausts and the left side was made slightly out of alignment - it fits but is under tension when fitted. The combination of heat & vibrations have caused the flange to split off twice; the first time I thought it was just bad luck/poor manufacture so I welded it back properly (only had minimal welding originally) but it pulled off again.

I then realised the alignment wasn't quite right (the curve of the pipe is not quite enough) so welded a new (thicker) flange on at a slight angle to compensate and whilst its' still not perfectly aligned (if it breaks again I'll look at bending it more) it is better and has lasted thus far.

My point being that spring fittings would allow for alignment/expansion/vibration and would never have broken in the first instance.

Also the Guzzi exhaust is mild steel whereas the Ducatis are stainless and I'm pretty sure stainless generally expands more with heat and is less flexible/more brittle so potentially the movement could be more of a problem?

Neither of my Ducatis have any leaking/sealing issues at the joints (at least not once warmed up) so I'd say the sealing is fine, on that I'd go with springs and flexibility given the choice.