Hi Norrie,
The standard systems are stainless steel and very well made, so unlikely to be blowing there - more likely to be blowing at coupling clamp. Its an easy fix, the three nuts and bolts on the clamp will be loose, but so rusty might as well replace them so the joint wil be tight. Of course if the system has cracked or damaged it can easily be welded.

If you do have to replace it, there's usualy some used system about as folks have replaced them with custom jobs, also at breakers. I have kept my original system as a back up after fitting a different system. A new factory replacement would probably cost more than our cars are woth!