Checking exhaust system for leaks

You can just feel around it while it's running and find leaks.

The vac won't hurt it if you go that route, but I can't imagine being able to hear a leak with the vacuum running:D
(the bubbles part), yea that would work if you want to spend a bunch of time spraying soapy water on your exhaust.

And then there's the smoke machine route. (a whole nother pain in the butt if you don't have one)