If changing interconnects does make an audible difference, there is something wrong with the design of some of your components! The goal of good electronics design is to make the inputs and outputs as immune as possible to different loadings, within reason. Just about any interconnect you might buy will be within the envelope of "reason".

In the days of vacuum tube equipment, input and output impedances were much higher than with solid state gear. The influences of cable capacitance and inductance was much higher, and certainly audible.