They do make a 2.9 kHz filter, which has superb audio for rag chews or nets, but would do nothing to tighten up the receiver against adjacent signals

I will compliment the audio on the radio

I've worked with contacts on 40m SSB to identify ideal audio settings, and for my voice and mic use style (very close and loud), Mic gain @ 60 and processor @ 65-70 (and turned on) seems ideal.