ipkha
How well do the noise reduction foams work? I generally read that they don't really help much with pc cases. I would think the front plastic panel would be the weak point noise wise and it'd be a shame to cover it up. That's why I use the Noctua DH15 and 140mm Noctua fans.
Personally I wouldn't use the foam on it's own. I'd treat it like in automotive industry: Dynamat on bare surface, foam over top. I wouldn't apply this to any visible surface, just to those that are hidden. Surfaces will carry the vibration regardless of it's source, so it's helpful to treat any surface you can. The only downside I see is more insulation, but the case has great airflow, so shouldn't pose a serious issue. Probably overkill, but why not go all out if I already have it! Also, I don't use dynamat, only said it since most are familiar with the name. there are cheaper thinner and better solutions out there. I like
http://www.raamaudio.com/ If you decide on foam as well, make sure it's ensolite or any other form of closed-cell foam. Open-cell foam is pointless.
Another quick solution is felt tape. fixes rattles quick, is very thin and barely visible.
https://www.amazon.com/gp/product/B000QDRRNE/