Bryston 7B SST

Bryston is offering to update existing Bryston 7B SST amp output stages to the latest "C" configuration used in the newest and very highly-reviewed 28B monoblocks for $250 per amp plus shipping. All new 7B SST's will have the "C" configuration. Has anyone had any experience with the new "choke" output stage in 7B SST amps? I use my 2004 vintage 7B SST's with very revealing Merlin VSM mme speakers and have heard that the update gives the 7B SST's a gorgeous top end.