Best method to move to new hardware?

My hard is old, my CPU is a dual-core 800Mhz and I have 2G of ram. Instead of upgrade that system I want to use my old gaming PC instead. It's a quad-core 3.1Ghz with 8GB ram. What would be the process of doing this? Ideally I use the same case I just swap the motherboard out, what will happen to unraid when I do this? I'd also like to upgrade to 6 from 5 during this upgrade to since it would be nice to be able to run my Steam games on it still using the new VM features. What's needed to support this?

Thanks,

Since you're already on v5, there's nothing to it.  Just upgrade the hardware; connect the drives; and boot to your UnRAID flash drive.

I'd do the hardware swap first and confirm all is okay; and THEN do the upgrade to v6.

UnRAID is great for moving between machines.  No issues at all, if the hardware works with recent Linux kernels, then it'll work with UnRAID. 

Cool, as other upgrades I'll just have to make sure the drives are still in the same order before starting?

Is this hardware good for unraid6? Can I run virtualization on it?

http://smile.amazon.com/gp/product/B004RQAJU4?psc=1&redirect=true&ref_=oh_aui_search_detailpage'

http://smile.amazon.com/gp/product/B004EBUXIA?psc=1&redirect=true&ref_=oh_aui_search_detailpage

Cool, as other upgrades I'll just have to make sure the drives are still in the same order before starting?

No, it doesn't matter in any way.  UnRAID tracks drives by their serial number.  You'll only need to note which is your parity drive, in case you need to reset the config or your flash drive dies.  I tend to keep the parity drive separate if I can, leaving a gap between it and the other drives.