AHH, so you have been there huh, well compound the fact that I didn't feel like taking the engine out of the car (either I'm crazy, stupid or just plain stubborn you pick) and you feel my pain.
Actually I must have been blessed, I took the previous VWHerb learned lesson of spraying each of those 2 huge a$$ nuts and everything else I planned on touching about 5 or 6 times over the course of 2 days before I even tried to budge them, I was using a combination of a pipe wrench, a monkey wrench and my Robogrips and the first one came off w/o too
much pain or cursing, the other decided to be real bad and after 2 days many untypeable verbal assaults and finally starting the car and letting the engine run for about 20 minutes it began to budge.
The pipe coming out of the heater box on the left side was rusted off about an inch outside the heater box, both pipes coming from the (old) muffler were rusted clean off from the muffler to the remaining clamp holding on to the heater boxes, and the muffler had about 1/2 a dozen open "wounds" needless to say, it was LOUD. I fashioned a new "engineered" pipe for the one coming out of the previously mentioned Heaterbox and the the real fun began.
Try putting that sucker back ON
the car without removing anything else, I ended up loosening the nuts on the front side of the engine on the Heater boxes and it gave me enough room to get it on.
All in all I spent about an hour or so at a time for about 2 weeks about every other day until Sat. morning when I was determined
I was going to be able to drive her that day and I'm proud to say I won.
Need to get my "engineered" heater box fitting welded up, I have a small exhaust leak but other than that it's sooo much better.
Sorry for the long post, after all that pain and suffering I wanted to share