Meowsterr

Hi, I'm relatively new to laptop hardware and I've been interested in upgrading my laptops gpu through a egpu. I saw the EXP GDC adapter and it seems that it draws power through the pci-e slot in my laptop (thats being taken up by the wireless card). My question is that the EXP GDC comes with a 220 W psu, so if I were to put the 750 ti ontop of the adapter would it still need additional power from a better psu? I'm really confused by this because on the nvidia website it says that the 750 ti needs 60 W as power requirements, but also 300 W, so which one is which?