I've recently been working following some of the steps in this thread for my '85 300D. My car has the vacuum set up described in this picture below but does not have the California air cleaner and trap oxidizer.

I blocked off vacuum to the EGR quite a while ago, then recently (about a month ago) I took the EGR valve off for inspection and found it stuck open. I cut a piece of thin aluminum to block off the EGR opening and put it between the valve and the manifold. I also cleaned out the alda banjo bolt at the back of the manifold which turned out to be pretty dirty. None of this made a noticeable difference in how the car ran.

Last week I followed the diagram below and blocked off the lines going to the EGR vacuum convertors and switchover valves (#81 and #84). The car is running noticeably better now; boost seems to come in quicker, I think it is shifting better and, when warm, it is idling much better.

However, when cold, it is starting much rougher than it ever has. E.g. it shakes more violently at first turnover then I ever remember it doing (I've had the car for four years). It's also putting out a decent amount of smoke as it tries to get going. After about 10-15 seconds it smooths out to about what I would expect for a usual cold start for this car, i.e. a bit shaky but not concerning.

Is this just a coincidence, or could messing with the EGR vacuum components have a negative affect on cold starts?