The Briley is 100% IDPA ESP legal because the Cuts are from the MFG (Briley is a MFG). Yes they use STI frames/slides but still a MFG no less. It is no different than the S&W cut up 1911's. It's probably the only Edge type gun currently legal because it has a bushing barrel. If you take a regular edge and throw a bushing barrel in it you would have an IDPA legal gun also.
The 2,000/20,000 rule is an SSP rule.