Just to close the loop. Bought the rear muffler by Eberspaecher from Fastlane. Delivered on-time for twelve bucks, installed with no hassles, fits perfectly, sounds fine. Highly recommend it for someone needing a stock replacement.
BTW - The muffler was OK. The noise was coming from a hole on the top side of the pipe at the bend just before it enters the muffler. Is this a common failure?