Place the wood chips in a bowl of water for 10 to 30 minutes, then remove and place them in a tinfoil package, leaving the top open.
Heat the grill or smoker to 250°. If using a grill, only use one side of the grill for the heat. Place the wood chips over the heated side.
Use a disposable tinfoil pan, or line a pan with tinfoil and spray with cooking spray.
Place the meat in a large bowl.
Combine the brown sugar, smoked paprika, salt, chili powder, garlic powder, onion powder and black pepper.
Coat the meat in the rub, pressing on all sides. Place the meat on a cookie rack and place in the smoker or on the side of the grill opposite the fire.
Close the lid and cook/smoke for 2 hours.
Using tongs, place the meat in the tinfoil pan. Raise the heat to 290° and place the pan back on the grill away from the heat side. Close the lid and cook for an additional hour.
Remove the pan and combine the BBQ sauce and brown sugar, then pour over the meat, coating well. Add slices of butter around the meat. Cover with tinfoil.
Place the pan in the grill directly over the heat and turn the heat up to 305°. Cook for 20 more minutes.