Accoeding to my calculation, the sensitivity cleaning (toward nearer 10^-18 [m/rHz] and remove peaks and bumps) "only" around 100 - 200 Hz can extend the range about  a factor of 1.9.

However, peaks around 180Hz are suspension sapphire fibers resonances.

Blue : KAGRA Displacement

Green : Simulated cleanline with better around 100-200Hz

Red: Simulated clean line with worse around 100-200Hz

Violet: 1.4-1.4 BNS Chirp signal projection ( 1/sqrt(5) factor is included )