The way GM timed the ZLE lap
is how everyone was doing it, so the time was apples to apples.
If you think GM was lying, then they are all lying.
https://www.caranddriver.com/news/a1...p-time-claims/
"The Nordschleife circuit itself, which does not include the modern Grand Prix course, is 12.9 miles (20.8 km) in length, but even that is not entirely accurate as it relates to these lap-record attempts by road cars.
Most of the attempts are terminated 656 feet (200 meters) shy of a technically complete lap, coinciding with the entry and exit of the small pit lane that most manufacturers use as their staging point, marked T13 on many Nordschleife track maps. Therefore, lap times are of a 12.8-mile (20.6 km) lap, not the full length"
"Who is scrutineer of the ’Ring-running cars for technical compliance to production-car standards, as would exist in organized competition under FIA, SCCA, or IMSA?
How do we know that they retain their production street trim and tune with legitimate production-issue parts?
Lastly—and here’s where the lap times start to bend under the weight of absolute truth—who is responsible for the official timing of the lap?"
The answer is:
No one.
"All the timing numbers and stats on the Nordschleife spreadsheet for a claimed “road-car lap record” must carry an asterisk with a caveat: “unofficial.”