The Euro intake would look great but not be any better performance-wise than the non-EGR OEM intake. I would also remove the crossover pipe if it hasn't been off under your ownership, to see if its getting plugged up.
The turbo certainly needs to be removed and serviced (new cartridge and balanced) based on the intermittent pressure readings you noted and the oil consumption.
BTW if you ask for it, the rebuilders will powder coat the turbo body while it's being rebuilt (that may add a couple of days to the turn around time) It will look better because it won't get all rusty like they get otherwise.
Dieseldiehard
1971 220 (gas) 4-spd manual 106441
1979 300TD w/ ’85 turbo engine 295530
1983 300D 243280
1985 300TD 217300
1987 300D 258230

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'95 E320 Wagon my favorite road car. '99 E300D wolf in sheeps body, '87 300D Sportline suspension, '79 300TD w/ 617.952 engine at 367,750 and counting!