Gosh, that's kinda a crap shoot. Best bet is to start it up and get the car on a lift and visually inspect the whole exhaust system from below. That's if you feel comfortable doing this sort of thing. Another quick and dirty test is to obstruct the end of the tailpipe with a handful of rags (don't burn yourself) and listen for any whistling or hissing noises. If there is a leak or hole somewhere, it will show up real quick. Rumbling types of leaks usually come from muffler or resonator.

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Jeff Lawrence
1989 300e
2000 Dodge Grand Caravan SE
No matter what you fix, there will always be something else to fix..
"Warranty" is just another way of postponing the inevitable.