i dont know about NJ but here in cali it is a hell of a lot ezer to take it in and have it done.it cost the same if you use there oil.
i use royal perpal but i still take it in. as for how much sorry i dont know
3.8 quarts is correct. I usually just put all 4 quarts in, especially if you heat the car up before draining the oil and let it drain for about an hour. I know this is anal, but I feel I am doing a much better oil change than taking it somewhere where they change the oil in 5 or 10 minutes.
Yes, heating up the engine to operating temperature is the best way to change the oil. Oil flows better when it is warm. By heating it up and letting it drain for a while you will get more of the oil and some of the sludge out of it when compared to draining the oil on a car with a cold engine. You just have to be careful not to burn yourself on the oil. I wear rubber gloves when I do my oil changes and keep a rag nearby just in case I do get some of the hot oil on myself.