Which wire has biggest impact?/


Trying to upgrade my cables- If I wanted to try a new cable which one would have the most impact-I know they are all important but which one would you start with- speaker cable- interconnects etc- thks
bopper
When I first got into cables I remember switching from the top of the line Monster Cable speaker wire to Furez 12AWG cable on a pair of Legacy speakers.  Furez speaker wire only run $1-$2 per foot.  The difference in clarity and extension blew my mind, it was not subtle.  I've been a believe ever since