forward SpeedUp();
public SpeedUp() {
    if(togstage == 0) {
        new
            vehicleid,
            keys,
            Float:vx,
            Float:vy,
            Float:vz
        ;

        foreach(new i : Player) {
            if (!IsPlayerConnected(i))
                continue;

            if ((vehicleid = GetPlayerVehicleID(i))) {
                new db = PersonalCar(i);
                if(db == -1) continue;
                if(db > 0) {
                    if(CarInfo[db][cStage] == 0) continue;
                }
                GetPlayerKeys(i, keys, _:vx, _:vx);

                if (keys == KEY_VEHICLE_FORWARD) {
                    GetVehicleVelocity(vehicleid, vx, vy, vz);

                    if (vx * vx + vy * vy < g_SpeedThreshold)
                        continue;
                    if(Carspeed(i) < 150) continue;
                    if (Carspeed(i) > (CarInfo[db][cSpeed]-2) )
                        continue;

                    vx *= SPEED_MULTIPLIER;
                    vy *= SPEED_MULTIPLIER;

                    if (vz > 0.03 || vz < -0.03)
                        vz -= 0.010;

                    SetVehicleVelocity(vehicleid, vx, vy, vz);
                }
            }
        }
    }
    return 1;
}