Hi Shane!
Good news regarding the pipeline!
The L/R bandwidth is indeed limited to 16k. If we make a full control version in the future, it will have options to go all the way up to 20, and full control over every parameter. It will be excellent value for broadcasters who need to really fine-tune their sound, and for whom extremely low price is not the key purchasing decision.

To my ears, though, the difference between 15 and 16 is much bigger than the difference between 16 and 20. I can hear up to 18 (just barely), but 16 still sounds pretty much like full frequency response. 15, on the other hand, distinctly lacks high-end.
The stream version will have the same back-end as Breakaway Personal, except that the whole chain will be phase linear. The FM back-end is indeed more powerful, but also uses much greater resources.
Good news though, you will definitely be able to use the stream version and the FM version at the same time, on the same machine!
///Leif