Tried over 10 cars here (mind you they were all modified to be as close to 450 PP it could, to see how fast i could lap here).
Also i was writing my best lap on my cell when it suddenly turned off; lost all my data lol. Anyway i'll try to remember the times.
I'll post some of them:
Alpine A110 1600S: one of the handlings i've seen in GT6, but too slow for it's PP. So slow that even being the best car in turns, i made one one of the worst times of all cars here. But also the one i didn't do any kind of tuning because it it basically doesn't need to (other than the transmission)... yeah it's that good on corners, Time: 1:29 mid. Good thing is that it's PP is so high that it won't make much of a difference if you tune it to 450PP or not, meaning it' still a easy win if you want to go stock.
Alpine A310 1600VE: king of oversteer, it is just as bad as the Lancia Stratos when it comes to steering. You can't even brake without almost losing control lol. Funny enough, if you can control the car it's a beast, much faster than the A110. Made a time of 1:25 low, the best time of all cars i tried... but just in one magical lap. The other laps i was just trying not to spin the hell out lol, which i did 2 times on last lap.
Renault Avantime: the car you can get the most HP for this race (i believe it's 360 HP), also the heaviest and the one that won't steer for nothing. After some tuning i could shave off almost 10 seconds because it began to actually steer lol. Time of 1:29 low
Peugeot RCZ : Piece of ****. I couldn't even get under 1:30 with this car. It's slow and pretty meh on corners. Time was 1:30 high
Citroen C4 VTR 2.0: this car surprised me. It has everything you want on a car: it's fast, turns nice and has very good stability. For 450 PP it's one of the best cars and the one i had the most fun with. It has one of the best handlings i've seen on a FF car, and it seemed to be the fastest car out of every one i tested (maybe behind only the Alpine A310). Time was 1:26 low ,slower than my best time with the Alpine A310 but damn consistent, since all the laps were on the 1:26 zone, and it's a FF!
While the A310... well, all but one lap were over 1:29 lol
Hommell Berlinette: another fun car, i bet most people used this one because it was mostly the only chance the had for using it lol. I did on 1:26 mid, slightly slower than the C4!
I'll try some stock cars now to see how they fare...