Good point on CW and filtering. About the only other mode besides CW that I operate is PSK-31. I have 2 mechanical IF filters in my rig for 300 and 500 Hz, along with the SSB filter that comes factory installed, the DSP, the RF gain controls, attenuator, AGC, and other controls. When I operate CW on a low activity band, my 500 Hz filter does the job of reducing noise levels and any nearby QRM and the RF gain or attenuator will help further reduce phase noise, improve SNR, and make a signal more easily copied. If the band is more crowded and noisier, the 300 Hz filter does the job. Furthermore, the DSP can be made narrow at the audio stage and further attenuate QRM A PSK water fall will often be as full of PSK signals as the entire band has CW signals. Really, a narrower filter than 300 Hz would be great to have...BUT, the higher the filter Q the more opportunity for ringing which can muddy the crispness of a signal. The lesson here is GET TO KNOW YOUR RIG and put as much effort into the receiver as you would the transmitter. Amps are great, but filters are even more essential for effective and efficient operating.