Historial para "How can I find out what is upgradable?"

I know that RAM, optical drive, and HDD are upgradable. How can I tell if anything else is upgradable as well? Will it be a worthwhile venture to  max out the RAM (to have 32GB, I have 16 currently), and swap out the existing GeForce GTX 860M for whatever the beefiest Nvidia the platform can handle? Will doing this add significant amount of gaming performance?

Dispositivo:

Asus ROG GL551J

Estatus:

open