Hi I am interested in playing this game with Linux, and I know Steam has some kind of compatibility layer to let users play games in Linux. I already bought KOTOR for WIndows here on GOG. Do I need the Steam version if I want to play on Linux with the Steam Linux compatibility layer?

Or will it work just as well playing the GOG version with that software?

Is the Steam version (for the first of the two games) any better for Linux?

I see the first KOTOR is rated Gold on ProtonDB for Steam's Linux compatibility software, and KOTOR 2 on Steam is listed as being Native to Linux.

Proton is a wine fork, and as far as I know, fully open source software. You don't need a steam version of anything, although you won't get a "one-click to run" experience unless you're using the Steam version of the game. I don't use proton myself, though, since I don't feel like keeping up with yet another version of wine.

I was running gog's KOTOR 1 & 2 flawlessly under wine (with and without a few mods, such as widescreen) years ago, and I doubt things are any worse now. Wine (and, I'm sure, Proton as well) is a fickle beast, and so KOTOR 2 is rated between Silver and Platinum on appdb.winehq.org.

The Linux versions of KOTOR are from a third party (Aspyr?), who refuses to release on gog.