Exhaust sounds really boomy like a chav exhaust, but it's original. Rear or intermediate silencer?

[kenbw2]

When I look at the rear silencer it says "PSA 12 96" (it's a '97 Xantia) so I'm guessing it's the original silencer and has crumbled from within. I'm a bit worried I'll replace it and find it's actually the middle one.

For reference the exhaust is Cat + Intermediate + Rear:



If it's loud and boomy like a chav exhaust, is it likely to be the rear one?

[white exec]

Try disconnecting the rear box, and see how that sounds.
If the rear box makes no difference, then it is likely shot.
Rear boxes tend to go first on petrol cars, because they run less hot, are are more prone to internal condensation.
12 96 has done well. Bosal were, I think, the OE manufacturer, so their catalogue may have it.

[xantia_v6]

From experience, I know that a rear silencer from a diesel Xantia sounds really boomy and unpleasant (especially at light throttle) if fitted to a 4 cylinder petrol Xantia. They look identical externally.