Arrange pork in large nonaluminum roasting pan or baking dish; set aside. Combine 2 Tbsp. (30 mL) brown sugar, 2 Tbsp. (30 mL) paprika, garlic powder, onion powder, cayenne pepper and water in small bowl; rub onto pork. Cover and marinate in refrigerator 3 hours or overnight.
Preheat oven to 350°F (180°C). Cover pork with aluminum foil. Bake 3 hours or until pork is very tender. Let stand 30 minutes. Pull meat from bones and place in bowl; set aside.
Bring remaining 1 Tbsp. (15 mL) brown sugar, 1 Tbsp. (15 mL) paprika and rice wine vinegar to a boil in small saucepan. Simmer, stirring occasionally, 10 minutes. Pour sauce over meat and toss well.
Spread buns with Hellmann's® Real Mayonnaise and fill with pulled pork.