From my own experience I can say that if the cars are changed to the same ones (only liveries change) and if you change car performance values in database.bin, then speed of cars in game will not differ much. In my opinion, the speed of cars should be configured not in database, but in ctf. files for each team car. For example, you can change the power value, taking Mercedes for 100 percent, Red Bull for 95%, and so on. There you can also find any parameters of the cars - mass, speed, revs, aerodynamic and so on.