Default Queries about upgrading to 4.4.2 and ROM

I'm currently on 4.3 which is a custom ROM since I cannot use Wanam Xposed (got recommended to me).

So I want to upgrade to 4.4.2 but with a Samsung ROM (if that's possible) so I can use that.

I'm new to this whole rooting situation so I have no idea where to go from here.