Buying GOTY while already owning base Fallout 4 game questions.

[Ponku]

I already own Fallout 4 base edition, bought soon after release. Now i thought about getting DLCs, but the prices seem kinda expensive :) With Season Pass 50€ or GOTY 60€.
But i can go to store and buy new box version of GOTY for ~33€ (which i think include Steam Key) Aside from how strange days those are that box versions of games are cheaper than digital ones :)
So, if i buy F4 GOTY, while already having base Fallout 4 on my account, i will receive all the DLCs for my already installed game when i apply the code?
Are the DLC downloads optional, or it just install everything like one game?
Especially if i dont want to install High-res pack (60GB download and storage space is too much..) will i have the option not to download it?

[Ricardo]

yes you can uncheck anything you don't want to install (dlc related).
now the goty many bethesda's goty edition are just bundled base game + dlcs not a diferent type of steam package so, yeah you should be able to just add the dlcs to your inventory with the key.