Well I have used this wire in several of my builds with good enough results.

https://www.madisoundspeakerstore.com/speaker-wire/supra-classic-2.5-speaker-wir...

Capacitors, well I've used Jantzen Silver Z's before, I've used Mundorf's too, heck I've used Parts Express.

They all worked.
My advice is to use as expensive as you are comfortable with, but maybe starting out on the cheap side just so that later you can change out to something more upmarket to see if you can hear the differences.