Full exhaust systems are available on line also.
I cant comment on the advice by your exhaust specialist. The exhaust is likely to be ten years old (if it hasnt been replaced already) and they dont last for ever!
An old blanket on the floor and a torch will enable you to have a look yourself.
The absence of your location information doesnt provide any clues ie North of UK & Scotland has more use of Road Salt due to weather conditions which leads to corrosion.
The detail of your vehicle is best placed into your Signature Footer which enables it to
automatically appear under every post. Info within the body of a discussion simply 'gets lost' with subsequent entries. When it is in your
Signature Footer it is always visible to any reader anywhere through the conversation.
Your World location also goes in your Sign-up.
How to do this is in this link (open fully to read it all) :-
Helpful Guidance Using the Forum