Well, I always get caught due to my crappy connection. But, I do believe cop cars are quite fast, aswell.
There Premiers Handling and speed just diff Texture
Same with Limo and taxi
However if your Cheetah has a Mod on it, it will make you seem slower to other players, even though it appears that your faster, keep this in mind, because a mod causes lag, it may no edit the Handling lines, but will make you seem slower to other players.
For Example, Player with a mod on there cheetah VS player with no mods at all
Winner = No Mods