Yes, you can use sirloin as an alternative cut. Just make sure to slice it into thin pieces before cooking. You can also opt for skirt steak or flank steak, both of which are more affordable options and will still provide a delicious Street Tacos Carne Asada experience. It is important to note that whichever cut you choose, it should be cooked over high heat and not overcooked for the best results. This will ensure your Street Tacos Carne Asada is both juicy and flavorful!