Had some of the Q for lunch just now - the sauce I made is way better today! I also added back some of the juice that came out after it rested.
This will be a regular thing...
This might be sacrilegious to many, but pulled pork ALWAYS tastes better then next day or thereafter. Sauce does as well. The flavors have time to marry and develop. Think about this. When you smoke a butt, the smoke doesn't penetrate very far into the meat. You could slice off the outer 1/8th inch and all you'd have remaining is cooked pork, just like you'd get baking it in an oven.
But, when you pull the butt and mix it up, all that smokey goodness on the outer surface gets mixed through but will also transfer to the inner portions. While sitting in the fridge, that flavor will continue to develop and permeate through the pork. At least, that's what I think it does. Granted, my taste receptors are kind of shot after messing with a smoker all day. I don't "taste" smoke nearly as well as others at the end of the day, BUT, I've had other folks tell me the same thing. That my reheated pork has more smoke flavor than it did the day before.