I haven't seen anyone remove unnecessary caps other than the differential output cap. What I thought was interesting about that is that the Tripath datasheets say to use a 0.01uF cap but the stock SI's use a 0.15uF cap. I've tried it with both and thought it sounded a little brighter with the 0.01uF cap. I couldn't really tell a difference between the 0.01uF and no output cap.
Other than that, the Tripath datasheet for the TA2024 and TA2021B tell you what values to make the output capacitors for 4 and 8 ohm loads. They say to use 0.47uF for 4 ohms and 0.22uF for 8 ohms. You could also change the output inductors to change the cutoff frequency and the filter Q according to the equations in the datasheet (just the regular ones for a 12dB/oct lowpass filter).
I haven't felt the need to experiment because I like how the AMP3 sounds stock

and I haven't experimented further on the SI because the AMP3 sounds better
