Hopa Divo VP37 Installation for VW Golf 3 TDI AHU

Hello everyone,
I'm new to this forum; so far, I've only been reading with interest, but now...
Let me ask a few questions; it seems like there are some knowledgeable people here.

I want to install a Hopa-Divo module in my Volkswagen Golf 3, 1.9L, 66kW (AHU engine), with 158,000 kilometers on the odometer.
Now, in this forum, when discussing such mileage figures, a...
It is recommended to have the fuel injectors checked to ensure they are still in good working order.
I also want to have that done by the Bosch service center.

Is there a specific inspection required after a certain mileage (e.g., at 200,000 km)?
then, again, it's important to do it correctly (I read that if the injection pattern is wrong, then...).
The piston can seize, and now I'm worried, but I already bought the unit?

I would also like to install the Hopa box in a way that it can be switched off.
"Hopa writes that the entire process should be approved by the TÜV afterwards."
However, the installation was carried out by a specialized workshop for Hopa systems.

Since the actual installation (which cannot be disabled) is ridiculously easy for me...
I would like to know in advance what the cost is for the shutdown function.
It would need to be done very precisely (I asked about the price, and the workshop wants 74 euros for it).

The VP37 has an 8-pin connector where the box is attached.
I just don't have any information about what the voltage supply is.

Has anyone ever done something similar before?

Regards,
Gromit.