Pretty much any hardware is good... one thing you'll notice is Crunching isn't as hard on the system as folding is. (Although a few Prime Grid WU's are a bear.)
I'm on a 3820 @ stock with 16 gigs of ram and 2 670's... works just fine. I also have a 4 P machine (6168's) with 32 GIG of RAM waiting for a new drive to come in so I can move it to crunching.
As you can see it's just standard stuff for the most part. The beauty of crunching is we don't get QRB for work. It's straight points so there isn't a 'build it faster to get a better QRB mentality'. You just install BOINC and roll...
As far as mining goes... there are some who do mine but Crunching didn't start as a mining operation but more like folding with a wide assortment of things you can Crunch... like Asteroids, Prime Numbers, Cancers etc. We (at least that I am aware of) do not actually have a Crunching@EVGA mining operation. Not officially any way.