Yes… i am familiar with tools…. But let me give you a example. Front wheels pivots. Changed in shop. Under 2000 km both. One has broken rubber. From bad replacement procedure by shop. I am one step away from hurting someone who doesn't tight the nuts and bolts on arms and bushings with the wheels in the ground. Even if i specifically tell them to do it by the book. Trust me….. It's that bad…. Normal
Shop or dealership.
I didn't know that engine Mounts are active. I will look into it.
I don't want to cha ge any engines. I had opinions with”change the engine” years ago with the W211.…. And it still goes strong and no oil loss or power. I was just explaining about the situation with shops and mechanics here. So… i have to figure stuff out myself and go to a shop and change only whats necessary and broken…. And not the entire car/engine.
I never over rev the engine. What i was telling its about the 2000 -2500 rpm range. And that is what i consider normal operating rpm. Indeed, if I Drive harder…. The car is spot on…. Extremely responsive. But that's not the case. I want in normal exploataion of the car all to be smooth. That would mean that all is in normal parameters. So…. Normal rpm range…. Normal pressure on the acceleration, normal car pace….
I am 42…. I don't drive like in my youth… 1st 40km…..2nd 80….3rd 120. All red lined.
Like i told.… on spirited driving mode… by me and the car…. The engine and gearbox seems tighter. And…. Less vibrations…
Previous owner told me he drove it in dynamic. I think in dynamic rattley and used tappers are not that obvious. Because more action in less time… and more pressure because higher rpm. Older tappers are worn and not that responsive to oil pressure in low rpm. Tappers don't compress and depress the same as new, in low rpm. That's why the vibrations on changing gears in normal and calm driving. This is my conclusion…. My idea. Will look into engine mounts…. Any link would be of use.
I hope you guys understand my ideas…. Based on aging of the parts and different behavior in different modes of driving and rpm. Aging parts are not broken, but for me, it's not good enough.
If i have fun with the car, real fun… pulls great, changes gears great, no smoke, no oil loss, consumption is ok. I could drive it like that…. But in my mind, not doing some stuff now, would make the engine vulnerable for later. And i want Tobe cautious

 

Ok, good.
I would start checking the mounts if there is the problem. For active vacuum pipes good way to test them is plug them on mount end and then blow on pipes right after the actuators. If i remember right the actuators for mounts are sitting on top of the engine, right next to MAF:s. Have you downloaded the x351 Service and Repair manual from sticky section? It would be great help for you, because its have all parts listed and systems very well descripted how things work.
There are lot of videos for mounts in youtube. Most XF or gasoline, but the idea/parts are pretty much same.
Check these:

 

Sorry for the late response. Busy with situations.
In short: the active mount solenoid has 1 line in and 2 lines out for the 2 sides. Blowing in them, the lines out that go to the mounts, and them holding pressure would mean that the lines don't have a leak and maybe the mounts are ok? Or it's not enough pressure for the mounts, blowing by mouth, but the lines are ok if they hold for sure? As I see, the lines are not clamped on the solenoid…. Ideas of what's the operating pressure for the lines and mounts?

 

They are operated by vacuum, so clamps are not needed. If there are no leaks, they should be Ok.
Peek underneath that the limiter bands are intact. (fabric bands should go around them, limiting the max movement)