They were talking about that frame over at pro-touring and at nastyz28. General consensus is it appears to lack lateral support and may actually use the engine to stiffen the frame. Many of those discussions go over my head.
There are a lot of cool sub frames out there. Some use stock parts, other use vette parts (like that one does, IIRC) They guys at pro-touring (and lateral-g) really have had long discussions on them. I want to do something like that in the 77
someday.