Yes, that's right, the roads in TDU2 are not flat at all.
I tested the Countach again and i reached only 290 km/H because of the traffic.
I will remove the traffic.
There is a bug : the rims of the Countach are much smaller than the tire. Please fix it if you can.
There is a bug with the size of the tires and rims of the Porsche 911 GT3 also.
I tried the mp4 12c and 911 GT3 and both are to slow !
According to your datas : the mp4 12 c is too slow about 1 second compared to real accelerations from 0 to 160 and 0 to 200 km/h !
It is unpleasant to drive : the speed is very long to reach : i see the speedometer going very slowly from 300 to 301 and then 302 and then 303 whereas the real mp4 12 c accelerates very much faster !
I have aleady seen a video of the mp4 12c and it reached 336 km/h and now in the game i can't even reach 326 in your road in Ohau.
It is a 600 hp car and not a 450 hp car !
Sorry, but even you want to do a good job, there is a problem indeed !
You could easily increase acceleration about 10 or 15 % to have a realistic acceleration.
Some gear ratios are good but some are still wrong.
And also : the road in Ohau where you do your tests has never been flat ! It goes downhill about 10 % !
When i take this road in the other side, it is uphill and the cars can't accelerate or even decrease in speed !
This road is not flat and not good to do your tests !
Your cars are too slow about 10 or 15 % ! If you test your car downhill, you think they are fast enough just because the road goes downhill !