I am thinking of swaping my entire motherboard, CPU and ram for and new bundle i found, What drivers will i need to uninstall?

It shouldn't boot up with an error screen or in windows, but we've all been surprised before. This is why we're saying to format your drive and perform a fresh install of your OS to help minimize the possibility of errors occurring.

Yes, backup your important files such as photos, music, films etc and perform a clean install of your OS. That is the general rule when it comes to installing new hardware such as mobo and chip. If you perform a fresh install of the OS it will pick up your new hardware and install as needed. You'll need to download a new version of the BIOS, and maybe some other things mobo related, but you can google those once you're up and running again.

Personally I would do a fresh install. A backup image of the whole thing is all well and good, but you might feel a lot better knowing that your new hardware and OS are starting off fresh. Then you don't have to deal with the issue of uninstalling previous drivers, programs etc. But that's just me.

Regarding that eBay bundle, and off-topic slightly, but I've just had a look at it. I'm somewhat confused by his listing and his description as they seem to contradict each other. Look at this:

"Pulled from my working system to upgrade.
It was working then but that was three months ago and unfortunately without taking everything out of my existing case (and I'm not dismantling all that water cooling stuff) I cannot test it, so sold as spares, parts, not working, etc, but was doing so admirably for the last five years."

So he hasn't tested it recently. Anything could've happened to the components inbetween 3 months ago and now. Not just that, but he's unwilling to test it. He's also unwilling to accept returns. A combination of these 3 raise red flags. Also, he says that he's selling these as spares/parts/not working but he hasn't listed it as such, he has listed it as 'used but fully operational and working as intended.' Another red flag. There are inconsistencies here. If I were you, I'd ask him to clarify the status of the listing and also if he would test it before you buy it to ensure that it is all working. You can't be too careful when buying computer parts on eBay.