I am looking for a cat back exhaust system for a 1988 760 turbo (IRS), especially the rear muffler. I have an 85 (non IRS) 740 parts car which has an OK exhaust system except for the rear muffler.

Can I use the front muffler and the pipe that goes over the axle from the non-IRS car on the IRS 760?

Where can I get either a cat back system or at least a rear muffler?

IPD only carries the non-turbo system and the local parts places aren't much help.