I, too, have wondered if this could be the source of some unwanted exhaust noise. Had the 240 on the lift yesterday for general inspection. The exhaust pipe connects to the inlet of the cat with a u-clamp. When momentarily plugging the tailpipe, we found exhaust puffing out from 4 slits in the inlet pipe that allow it to telescope over the exhaust header pipe. Evidently the inlet pipe won't telescope far enough to seal the slits completely. When the tailpipe is not momentarily plugged, you can't hear any puffing sounds (engine idling), as you can when it is plugged. What I'm wonder is......will these exhaust leaks directly beneath the front passengers cause a fairly good resonance inside of the car when running at highway speeds, engine rpm 2000+? The mechanic here said no, that such small leaks wouldn't be heard inside of the car. Since it is upstream from the cat, I'm thinking otherwise. Who's right? I still don't think that this car, a 93 240 sedan, should have such an obvious exhaust note (not deafening, but definitely audible) heard inside at 60mph. The tires and windnoise should be far more obvious than any exhaust sounds at that speed. The rest of the exhaust system checks out perfect, no rattles from cat or mufflers, no other holes anywhere.