https://www.youtube.com/watch?v=yuJwAcD0Efk The collector .11 AX that is being discussed. I did not know of a standard AX .11 being offered. There is a car .12. A billet case is arguably stressed from machining. Sometimes big cuts heat it up too much. It is a good option for small runs. Sometimes the roughest sand castings are the most stable. A motor will distort even while running so it is not really a big deal.