Make macaroni shells and cheese according to package directions. Stir in 1/2 cup sour cream. In another pan brown 1 lb. hamburg and mix with one package taco mix. In an 8" baking dish layer 1/2 the macaroni, then all the meat, the rest of the macaroni. Top with salsa. Bake in oven at 325 for about 1/2 hour. top with shredded cheese, bake 5 minutes more....Enjoy!!!!