I’m not a big fan of Cortex myself. I run a Firefly game now, but I Savaged it. I have some of the Serenity books, which are nice for ‘Verse information and the like, especially Six-Shooters and Spaceships which adds a bunch of gear and a number of spaceships, some with deckplans and the intention to be alternatives to a Firefly for a PC ship.