Rewired the Eurocom last night. Ended up splicing a couple female, three-pin connectors into the original fan header, so that I can use any fan or low noise adapter that I want to. Spliced some male, three-pin connectors back onto the Noctua fans, and threw in some adapters to bring the decibel level down... fans are super quiet now. I can hardly hear them, even when I've been gaming for a while.
I'm half tempted though, to get a couple slim 92MM Noctua fans for it, and mod them to sit on top of the enclosure. That way, I'd have even more airflow for the unit, and it would be even more quiet. If I did that though, I'd HAVE to model and 3D print a new cover for everything, lol.