I just checked the engine.ini and the ai.ini of that mod. The rev limit of the engine is 3700 and ai should shift up at 3600. Maybe change the UP=3600 to UP=3500 in the ai.ini and see if it works? Or make the DOWN much lower if the gearing is so long it drops below 2300 when shifting up. Try DOWN=1900 in ai.ini.
I think there is a setup on the AC Forums which is meant to make the car more enjoyable, not sure. I have only tried it offline at Brands, and I must admit it was good fun, might have a look for an online server tonight
He is trolling , there is not one single bad comment on AC or VirtualR forums
Of course this car is not for everybody, If you like difficult handling cars with soft suspension, poor grip, shity brakes, with some quirks, like famous front end lift at high speed, to high revlimiter, etc. Then you will love it