Correction:
They will replace the Trap and Turbo!One time only. They replaced the trap oxidizer with a Trap Cad. look like orignial. The dealer can get the info off the computer for you.
Now to the "they owe you a replacement pipe." I went to five dealers and for my 85' california car there was no replacement pipe from the factory. There was one for 86' and 87' but this is a six banger and different length.
Options.
Get Trap off and have muffler shop use mounting flanges and make you a replacement pipe.
Or go to bone yard and buy Intake and Exhaust manifold and Air cleaner and bracket as well as line for turbo {there are two of these} plus the plastic U-shape hose. From a 84 or 83 turbo. And the first exhaust pipe. Buy new gaskets.
While you are there you should plug EGR port and remove it.
Of course all of this removes smog equipment and is illigal and wrong. So it is just theory.
Boy do I like my theory without that trash on the car.
Charlie