As they are directly in the signal path, upgrading your rotary switches and potentiometers can lead to surprising effect. However, real audio grade switches and pots are becoming increasingly rare.
Never underestimate the importance of the volume potentiometer. It has a dramatic and clearly audible influence on sound quality. Get it right, and it is an open window to the musical performance...get it wrong, and it will crush sound completely. Surprisingly, some of the most frequently used and well-known volume controls - often advertised as a particularly 'audiophile' feature in our competitors products - actually sounded the least satisfactory!
Hence we started to build our on stepped switches, while we continue to supply premium carbon pot-meters.