Help - 996 developed a rally car bark

[stoobies]

My 996 cabrio has started barking like a rally car (sounds like the exhaust has a hole in it) but its more complicated than that, its only coming from the passenger side of the car and once the engine heats up the rally car bark disapears,

'is there trouble ahead???'

[Weltmeister]

Could be a Cat Converter leaking a little, as they warm up they get quieter ?

Allan