I already have a grinder with the tubing accessories etc...Can I use those for making sausage, brats etc or do I need to also buy a sausage stuffer separately?

That will work fine for large diameter sausages, but if you want to make smaller sticks its best to use a stuffer so you dont mush the meat. Also if you like to add Hi-Temp cheese to your sausage you should always use a stuffer.