Originally Posted by Bimmer-Bob

Thanks again for all the helpful replies.

Bear with me, as I'm new to diesels (and Mercs in general), but I've been sifting through as much info as I can find and have come up with the following plan of attack - I'd appreciate any opinions on whether or not I'm missing anything important, or am including anything extraneous.

So, to start, I think I might do the mechanical wastegate conversion and EGR delete. Can't hurt, might help, and at a minimum it will simplify the vacuum system somewhat and minimize potential points of failure. Next I will inspect the condition and function of the vacuum pump. If broken, or old style, will replace. Next will inspect (and ideally replace) all lines and fittings branching off the 3 lines from the VP. Since I'm having shifting problems, I will pay special attention to the VCV (is this an easy and cheap thing to replace?). After all of the above is done, I should be done in the engine bay, is that correct? Then I will move under the car and check the transmission modulator, and replace as needed.

So far, so good?