My preferred method for obtaining fuel (from early game even through to late game), is to wrench cars and pickup all fuel when looting so for me it would be fuel saver mod; by the time i get a chemistry station i use it primarily for making gunpowder, not so much for turning shale into fuel. some things in the game (even late game) i like to do the harder way, ie in late game everything can be too easy, so i "slow things down" a little by obtaining fuel the hard way ; i do of course turn shale into fuel if i have it, but i just don't often go on mass-shale gathering expeditions anymore