Or just apply, it's not that hard.
I'm not sure it's possible to get accurate data, since there are numerous factors your speed depends on, such as the type of the road you're driving on (i.e. roads like the main one in The Strip slow you down), FPS, .dff car mods (surprise), your connection, the script, etc.
Ten people can drive the same car and have different top speed.
This.
Mission impossible.
Well. I'm using a clean version of GTA:SA.
Testing the cars their speeds on the entire Julius Thruway in Las Venturas.
FPS is around 30. Connection is great enough.