so if I read and understand correctly, i can order pieces later to turn my 510 into an ego/tornado?
Yep. What Jerry said.
Even having one tornado battery helps and while the cone isn't absolutely necessary - it is nice and I'm persuaded (by Scottbee and my own experience) that it helps with performance - it controls and tends to heat the airflow. But you'll have to get the charger too. The regular 510 charger won't work without an adapter.