St. Louis style and spareribs come from the ribs closer to the belly of the pig, the only difference is that spareribs aren't trimmed down. If you go with spareribs, be aware that the piece will be larger. This isn't a problem if you've got a little extra time to cook them. And you'll want to double the rub and sauce ingredients. You can also go with baby back ribs, which don't come from baby pigs--they're actually just smaller ribs, from farther down the spine, closer to the loin. Because they're smaller, you'll need twice the amount of ribs. They also take less time to cook.