Not neccessary. It's possible to re & re both strut mounts & bearings without compressing the springs, done it many times.
That's easier than swapping a couple of nuts and jacking up the car a couple of times ?!?
I had a small radiator leak for 5 years, only leaked in winter when I parked after a highway run in outside temps well below freezing.
One summer day it let go in a big way, but after refilling with water l was able to get home (200km) by running the system unpressurized.
If the N75 output test is smoothly cycling the turbo between no boost and full boost (against the stop), and there is no leak down from the full boost position, then the actual vacuum number doesn't really matter.
The difference in meter readings probably explains it. The ECU sends a PWM (pulse width modulated) signal to the N75, and you have one car where 0% duty cycle translates to 10.7v, but on the other 0% reads 11v. Different tunes maybe?
When the insulation in the door jamb cracks it can allow wires to short together and blow fuses. Every time you open or close the door, you may or may not blow a fuse. Other strange things may or may not happen too ;)
The same wire flexing issue can also occur between the body and trunk lid...