Can I add extra RAM? Are there any DIMM or SIMM slots on APC?

Updated: November 10, 2015
No, it is not possible to upgrade the RAM on APC. There are no additional DIMM/SIMM slots.

Does APC support SATA or plug and play hard drives through the USB ports?

Updated: November 10, 2015
It is possible to add a hard drive through USB as long as it is FAT or FAT32. APC does not have any onboard SATA connectors. USB drives under Firefox is on the list of known issues on GitHub.

What is the max capacity for the microSD?

Updated: November 10, 2015
The max capacity for the microSD card is 32GB, allowing you to add ample storage space.