Honestly the late 90s GT classes were a crapshoot at the best of times.
You had a short tail F1 GTR run by Parabolica in GT1 in 1998, despite pretty much being a GT2 car at that point in performance.
The Lister example he gave is kind of weird to me because the version he referenced is the GTL, which was specifically made to try and bump the Storm up to the prototype level that the other GT1 cars were at, but the regular Storm was a GT2-early 2000s GT1 car. So it wasn’t really the same car honestly.
Then the Mosler I think originally raced in the equivalent GT1 class at Daytona in the early 2000s, so it being in N-GT is a little weird because the de-tuned version was the MT900 GT3 which came in ‘06 and was definitely not an N-GT car.
Then the Marcos, the Mantara LM600 was also a late 90’s GT2-early 2000’s GT1-spec car. The Mantis racing cars or “GT3” would have been a much better fit for the game’s N-GT class than the LM600.
Honestly some of the stuff in the game, they just made it up. But in reality often cars weren’t really put into classes that made sense either. That F1 GTR really should have been a GT2 entry to give it a chance.
The correct answer to all of this confusion is to blame Porsche.