So I removed the vacuum line from the waste gate and ziptied the wastegate actuator arm in place and performed 2 test drives; one with arm all the way out, one with the arm all the way in. I wasn't sure which would be open or closed so I did both :-).

Under test drives, I did not achieve any boost. To me, this eliminates the wastegate (or valves or vacuum controls operating the wastegate) as the root cause of my sudden power loss. A pressure actuated wastegate is on my long term to-do list, but it's taking a back seat to finding and fixing current power loss situation.

This circles me back to original ALDA questions:
1.) If a capsule popped is this repairable, or does the whole valve have to be replaced?
2a.) If I need a new valve, where the heck do I buy one...I can't find any online!
2b.) If I only need parts, are these parts readily accessible (ie generic o-rings) or are they MB specific parts and, if so, where can I source parts?
3.) My intake needs to come off for other reason (cleaning out EGR gunk and to gain access to glowplugs for replacement and pre-chamber reaming). As long as I have it off, this would be an optimal time to replace/service/repair the ALDA. I'd love to avoid unnecessary knuckle-busting; is there a way to rough-in ALDA adjustment while I have the intake off?
4.) Follow-up; anyone have an exploded view and/or parts diagram of an ALDA of this generation?

Brad