Suggest you discuss the convertor needs with the trusted trans shop....if this is a street daily driver...no need for a billet...
As someone who has built well over a thousand transmissions I would never provide a trans without my own fully rebuilt convertor....rebuilt as in cut stripped pressure hot washed, and re-assembled with new parts as required.
Also, when installing the trans and convertor, make sure you / they fully flush the cooler circuit and preferably install an external cooler system that totally bypasses the oem radiator cooler system....plug those radiator cooler ports to keep out the crud...
