Putting resistors across the output capacitors is not a great idea, I would suggest removing them to prevent any unpredictable damage. You're also putting a standing DC current across the inductors at the output; this is a detriment to performance.
The capacitor and inductor in the output stage of the Quicksand form a tuned filter. Changing the value of the cap changes the value of the filter (also not necessarily a great plan).
The Nichicon KA capacitors that we provide with the kit are their current state of the art capacitor purpose made for audio. The Gold Tune (KG) caps are an older design and less expensive than what we already provide.
Changing the 1uF caps at the input is, however, a good mod to do to the circuit. One can put a wire jumper in where the current 1uF caps are and place 1uF film caps between the center solder wells of each RCA jack and the PC board input.
