Good afternoon, John --
You don't say in your post whether you _initially_ had the problems that you are describing or _after_ you did the procedures described.
If the problem happened _after_ you changed filters, I would guess that you may be pulling air at your primer pump. Either the pump knob was not securely closed or it may be leaking anyway. It's always a good idea with the 617s to keep a spare for this very reason (not to mention that the primer pump may stop working at the precise time that you really need it!). Even if your problem was being evidenced before you started working on the car, it still may be the primer pump. I would check this first.
On the turbo boost adjustment procedures, the procedures for checking the boost sensing lines and checking and adjusting boost pressures can be found on my site at: http://hsb.baylor.edu/html/easley/autofaqs/main.htm
Note that I would _not_ recommend adjusting your own boost unless you are a confident, very competent DIYer. On the other hand, if you do fit the above criteria, I would not hesitate to do the adjustments. You will find the results most pleasing, with no reduction in the reliability of the 617 engine, but dramatic differences in the performance of your car. Adjusting the boost to proper levels (and within MB specs) is a procedure that will significantly benefit probably 99% of the 617-equipped MBs on the road, yet virtually no one was talking about it until Stu Ritter (Technical Editor of The Star, MBCA's club magazine) alerted me and other DIYers to its advantages about 5-6 years ago. What is most surprising to me about the procedure is that I believe that many MB techs do not even realize that is possible to do. For example, about 3 years ago I was talking to one of the most senior MB techs at one of the largest dealerships in the southwest about turbos and performance adjustments/modifications. Not only did he work in the dealership, but he also owned a 617-equipped MB. And, though this sounds illogical, he said that the shop had regularly (and frequently) replaced turbos in the past for inadequate boost, not knowing that they could be adjusted.