Cloning your HDD to SSD, with everything else constant, is one thing (though it can be problematic).
Trying to avoid reinstalling the OS, with major unrelated component changes involved, is never worth it for a continual use 24/7 rig.
Recently did a i5 2500k budget build for a cousin.
I have to say, the Diablotek Evo is surprisingly decent for its price (grabbed it at $27.99 from micro center). I was surprised to see it came with 4x 120mm fans, psu/front filters, and 1x 2.5" mount.
Its only flaws are
1) slightly noisy tops fans
2) small space (definitely on the small end of "mid towers".)
3) Not tool-less.
Other than that, the case was honestly better than some of the lower tier lancool/lian-li/cooler master cases I've dealt with.
I'm don't know if you bought it based on the OP, but the reasons above, and its build quality, are exactly why it's in the recommendations.
Even Cooler Master can't compete with the Evo at its most common price points, unless you find a discounted HAF 912. To CM's credit, their sub-$50 options just fall short as an overall proposition, unlike Thermaltake which sells tin cans masquerading as computer enclosures.
The slight fan noise coming from the top 120mms is due to their bearings. That bearing type never does well in horizontal use. Some same-ish fan models are just more susceptible to the effects of horizontal placement than others.
You should try oiling your top exhaust fans, and, when you're able to, replacing them with a better set of budget options.
Question about this:
I have a windows 7 upgrade key, which was originally used on a bootcamp partition on my macbook. I don't think I formally uninstalled it, I just deleted the partition because I wasn't using it.
I still have the key and could get an iso for the upgrade, I'm sure.
Could I install it on my new build and not run into trouble?
Yes. If you don't pass the online verification, a 5-7 minute phone call verification normally works.
