Modifies a vehicle's top speed.
This is the native you have to call when trying to apply handling changes related to fInitialDriveForce and fInitialDriveMaxFlatVel via the SET_VEHICLE_HANDLING_FLOAT native, otherwise your changes won't apply.
Calling this native will initiate transmission setup for the given vehicle so any transmission related changes apply, it will also update the drag coefficient on the vehicle based on the percentage change.