When the production engine exists in physical form, we can absolutely discuss its capabilities. The XB-1 demonstrator is, using afterburner to get to speed, demonstrating other design features intended to keep the noise down.
The original plan was a commercial partner for the engines, but the big three - Rolls-Royce, Pratt & Whitney and General Electric - turned them down. It's one of the biggest remaining question marks in the entire project.
