Another user with exactly the same problem, It is not possible to install HDD into cage without them overheating as there is so little airflow, even installing fan in the side panel does not help much, as most of the air flow from the fan goes out the PSU intake grill and through the PSU its self.
You need to install an exhaust fan on the HDD cage door to pull air over the HDD to keep them cool, or risk frying them.
It is a fantastic case otherwise, but it looks like they neglected at engineering the airflow on the basement section. The top / motherboard section is great.
What would make it perfect is if they put in some hot swap HDD bays with dedicated cooling.
