Better handling and better control , increase in accleration , the crash dynamics are same , the top speed is 420kmph.

car mod used-https://www.gta5-hub.com/vehicles/2022-lamborghini-countach-lpi-800-4-add-on-template

I dont how the car actually feels while driving , so yeah it maybe not the realistic handling for the Countach but it is good for gta5.