So I have just conducted the test with BOP on, decided to use two US tracks that are barely changed layout wise from how they were around 1997-1999: Laguna Seca and Road Atlanta. Here's the results:
Mercedes CLK LM (581 HP)
Laguna Seca: 1:18.600
Road Atlanta: 1:14.560
Toyota GT-One (566 HP)
Laguna Seca: 1:20.047
Road Atlanta: 1:15.051
BMW Mclaren F1 GTR (602 HP)
Laguna Seca: 1:19.166
Road Atlanta: 1:14.440
Test 1: The Mercedes is unsurprisingly the quickest at Laguna Seca. It just feels mechanically the sharpest around this tight little low speed track, which is not too far of its dominant pace here in period circa 1998 (Not even the talents of Allan Mcnish could save this movie from going the way it did). The Mclaren is second, its surprisingly decent but you can feel how less polished it is. That front end just lacks that sharp feel of the Mercedes (Its especially exposed at the Corkscrew), but otherwise its not bad and that power keeps it just close enough on the few spots I can stretch its legs. The Toyota is at the bottom and its not hard to see why: That car was singlehandedly made for one track only and Laguna is far from it. It feels like it just stalls in the slower corners, requiring much more brake and what feels like far more wheel lock. It just doesn't belong on a track that is the Road Course equivalent of a Bullring.
Test 2: The Mclaren is the quickest here. Handles the faster corners much better at Road Atlanta then at Laguna Seca, still is handicapped in the slower spots but that power basically saves it as soon as it gets to the straights and at a Mid-Speed track like this, it matters alot. The Mercedes is second quickest but not by much, it retains that Mechanical sharpness in the corners so it manages to keep the gap close by the time the straights show up. The Toyota is again the slowest, its actually decent here since its abit closer to the type of circuit its built for but its the power that let's it down this time (Not helped by Turn 10 being its Achilles heel, allowing the other two to power away)
Hope that helps.