Good luck opening your shop. You'll have to let us know when you do, I'm sure there are lots of us who are looking to add an older restorable MB to their collection (your collection seems to be about the biggest I've seen in a signature)
How much time and labour was involved in fixing your rough idle? I have to have the car pass emmissions in a few weeks to re-register it. I took it in for a test this morning and it had miserably failed the hydrocarbon test (288 against a limit of 103). So I am sure I am looking at a valve problem, and I am pretty sure I know which ones. The car will visit the mechanic once again this week and I am specifically requesting they look for what was wrong with your car (so far no one has bothered to look). I am just curious as to how many days they will need to work on the car.
1995 E420 - retired
1986 420SEL - retired