This is a point of debate from time immemorial so i dont want to stir up a hornets nest choice is always there
but in my humble opinion and from my own reading there is no scientific eveidence or explanation which justifies expensive wires and interconnects rest is up to buyer.
I believe order of money spent should be from High to low
speakers
HU
sound damping
amp (google richard clark amp challenge for some very interesting reading)
wires/interconnects