Maaann, I'm already in Spa mode. Ran all 27 cars, 1 lap, right after one another, no practice, mistakes, and no resets. Spa default conditions, TCS 0, BoP On. All player's results will vary. This is what I found in my hot lap journey.
I'ma try to keep this as brief as possible: 'If your car doesn't turn, you're toast.' - 05XR8
First of all, the Genesis. I blah blah blah about the Scirocket's off-throttle turn in. Well, the new found king of the off-throttle turn in, is the Genesis(at this track). That's why it's up there. It was 3rd fastest through Eau Rouge(5th gear, 215km/h). The Huracan was second fastest at 216km/h. RC F was flicking 215-216. Next, the Genesis transformed tight turns into straights. Didn't put a wheel wrong. Fitting name, as it might be "the beginning" of me enjoying this car, again.
Most stable was Viper. i messed up in the final chicane. I suspect it would have matched the C7's time( C7 was easiest to steer). The GT-R was just as stable as the Viper. Like a rock and impressively quick everywhere.
Keep this one a secret. The TTV6 "felt" strong. Excellent power delivery.
86 was/is the most fun. Throw it, chuck it, fling the thing into corners and it's absolute fun. Sounds great at this track. Just winding it up and speed on through the lap.
WRX. What can I say. It's a silent assassin. Didn't expect it to match the speed of the fastest RC F through Blanchimont(228km/h). The Scooby Rex came on strong from the beginning of the downhill(Bruxelles) to the final chicane. I think it might be a problem come next week.
458 is the best sounding. I got immersed in just driving the thing. For a virtual experience, it's like a proper race car.
RC Z is up there on sheer top speed. That's it. Not even close in handling to the Scirocket.
Cars that fell outside of the 20: Alphabetically, the 4C was fast through Eau Rouge, 221km/h

. From there, it was stuck on cruise control. It sliced through the corners, but doesn't have that top end. Sorry. Same for the Slophy. It's going to get murdered if there is a horizon in sight.
Citroen wasn't flash either. Thought that might be a sleeper - it literally was.
At 1650kg, the OyVeyron is a porker. Hey, if anyone can make some magic happen, good on them. Maybe if we could swap in the Scirocco 2.0T, it might go better with less weight.

Where is the TT? Oh right, garbage(like a garbage truck). Why won't the thing turn? Thought it would blitz the field and be in the top three. Oh well... Maybe the R8 GT4 will pop up some day.
Lastly, that AMG. Wasn't magic on the straights or braking or accelerating, but BOY, its mid-corner speed and handling, enabled me to be very early on the throttle. I was mashing the trigger just before apex. That's right, mashing it. Nearly forgot it's FMR. No waiting. Point it at corner exit and mash it.
All in all, it took me from the start of Total Recall(1990) to the end credits. Some may feel these cars are slow, but it was full throttle for most of the lap. Should be a fun combo.