Cook (reheat) the sausage according to the package directions. (I like to cut mine into 2"to 3" chunks and split them lengthwise to get a little more char on the pieces.)
Bring 6 cups of water to a boil over medium heat. Stir in the salt.
Carefully whisk the grits into the water. Reduce the heat to a simmer, cover, and cook for 10 to 15 minutes, or until tender, stirring occasionally. You may have to add a little additional water if they become too thick.
Once the grits are tender, stir in the butter, cream cheese, and cheddar cheese. Stir until the cheeses are melted. Stir in the pimientos.