there are three mufflers on my 87 300e, one just after the gearbox near the front flex disc, one under the rear seat area and the final box with the tailpipes.

I don't have a cat on mine so can't help with its location. it may or may not replace one of the mufflers, but i don't think so. I think its between the front muffler and the engine manifolds

__________________
1987 300e manual 250,000 km (sold)