Have a friend sit in the car after it's warmed up and revv it while you're half under the car (off jack stands btw) and glide your hand around. If there's a minor leak you will feel it. If there's a BIG leak, you will
see it. There will be black soot collecting on the ground.
Hope that helps. Definately find out where the leak is before you go replacing stuff (but a completely new exhaust system doesn't hurt!!
)
