Makes sense. From your dyno, those extra berk rpm's may gain a few extra hp's (6 hp?), but maybe not enough to see on the speedo as your hp curve is relatively flat from 5800 to 6200. (JPC says 150 rpms Legend B to Berkeley B) Considering the price of a new Legend SS, an existing MPD detailed Berk SS at a cut rate sounds like a good deal to me. I doubt you'll lose speed with the swap. And SS rules!
jer