Using a noise source and a QA400 audio analyser we tested the filters in an FT-817.
Stock Ceramic SSB filter: surprising poor skirt selectivity. Probably the result of insufficient isolation between the input and output on the FT-817 PCB.
For comparison, we tried adding a WOLFWAVE. Note how the skirt performance issues are improved by a wide margin ( >40dB in some cases). This will make the radio sound much better due to the rejection of interference outside the filter passband.