This is a good match up and it is hard to decide on a clear victor. Sasuke does have CS2 so I'd give him the victory here.
Darui's advantages
Black lightning
Slightly better kenjutsu
Slightly better stamina
Water>fire
Sasuke's Advantages
Slightly better speed
Sharingan precognition
Genjutsu
Cursed seal levels 1 and 2 (Increased power, speed, durability and healing)
I'm giving the victory to Sasuke with mid-high difficulty since Sasuke's attacks become more powerful, healing abilities increase and he gains wings to help him fly/defend himself. Also one of Darui's lightning attacks did not faze 3 tomoe Sasuke so I'm inclined to believe that CS2 Sasuke can tank Darui's attacks with the help of his wing as defence. Sasuke's paralysis genjutsu and superior speed also makes me inclined to believe that Darui will have a huge disadvantage in this fight. While Darui does have an elemental advantage, Sasuke is clearly better than him in all other areas.