T4 MKB Tax Markings: ACV

Hello everyone!
I would like to get some expert information about the markings on the engine mentioned above.
I need them to determine with 100% certainty whether the vehicle's tax markings are correct.
He's actually making these little spirals:
The maximum speed is 140 km/h (which is exactly where the green area of the turbo gauge ends).
The performance is actually okay, but the owner thinks it used to be better.
The preheating light blinks intermittently while the engine is running.
It's hard to start.

The owner of the car had the timing belt replaced approximately 2 months and 15,000 km ago (high mileage). Since then, the problem has persisted. He has already been to the same workshop three times for repairs to try to fix the problem, because the car wouldn't even start after he picked it up from the workshop. They then quickly installed a can of 'Startpilot' with a holder (like those used in older Mercedes Lkw trucks). 'He should rev it up while starting,' they said.
The problem has only slightly improved. It does use less fuel, but it only reaches 80 km/h in fourth gear, and in fifth gear, it slows down on a straight road despite full throttle. It was taken back to the same workshop: they then installed an electric pump in the fuel line leading to the fuel injection pump.
and on top of that, it was completely without any safety features and leaking, and it had air bubbles in the diesel line!
Problem not resolved, returning to the workshop.
'To solve the starting problem, they disconnected the connector from the temperature sensor to simulate negative temperatures for the engine control unit, which results in the maximum possible glow plug duration. They attributed the problem with the performance to poor compression values. When asked why the compression values were poor, they said (quote):'

'Logically, the engine is broken - it already has 691,000 km on it... but I could offer you a cheap used one.'

So, because in my opinion this workshop is absolutely INCOMPETENT, the aforementioned gentleman came to my workshop and complained about his issues.
Appointment made - Hood opened - Vacuum system checked - The LEAKY pump removed, along with the starting fluid - and since the first error should have been obvious to a workshop that's part of the trade association, the seal on the intake hose directly at the turbocharger was missing. This resulted in a significant amount of unmetered air. Connector for the temperature sensor reconnected. Compression checked... etc. etc.

Now I've gotten to the point where I've removed all the built-in errors, and now I want to check the timing. Because if someone makes such a mistake, I wouldn't be surprised if they installed timing chains instead of timing belts. }

You're probably wondering why I'm posting all of this. But I believe that things like this should be made public. It's exactly these shameless, incompetent people who are damaging the reputation of qualified workshops, and forcing some workshops to close due to a lack of orders.

Regarding the car:
He really has 691,000 km on the odometer. However, it was only used for long-distance driving and has a complete service history. Once, a service was performed 800 km beyond the scheduled interval, but that was only because the owner wasn't near his usual workshop at that time. (By the way, that workshop closed in the spring of this year due to lack of orders -> that's why it ended up at this particular workshop.)

The compression is exactly the same on all cylinders: 19.5 bar.
That should be fine.

Okay, I need you to mention the reference marks for the tax-relevant components of the electrical system on the first page of this novel.

Thank you in advance!