I got a custom built rig when the gtx 1080 first came out , mine is the zotac version. I have all settings on the games I use maxed out and I never even here an increase in fan speeds. I note you put your price limit in dollars , I am in England.
With regards to changing component's you already have I would suggest you email the makers of the card version you intend to buy as they would best tell you if you need to change any of the component's you have.
A FEW TIPS … don't use the nvidea experience part of the software that comes with the driver package as it does what it THINKS you should be doing and not how you might want it set up. To make sure you don't get given the experience part in a driver update , get the update manually and during install untick the experience box. You might also find an experience tab in your start up menu that you need to disable.
Here's an odd one for you , their is an overclocking program on the disc , when I installed it I thought I was installing a free game. I wrote to the makers of the card as I know nothing about overclocking and did not want to risk damaging anything. The individual who replied to me said the 1080 has the ability to overclock itself if pushed hard which begs the question , if that's true why is that program on the disc.