The 155 BHP figure quoted by Suzuki and Bimota, was at the crank, and it was a bit of an exaggeration.
I know most of the guys on the Bimota forum that run SB6's are all seeing about 130BHP at the rear wheel, so your 125 sound good to me
PS.
The Bimota SB6 runs the GSXR1100 WR / WS motor.