For talking back, I think you need to look at what your DS really cares about, and explain that his respect for his parents, teachers, etc. is as important as those things that he loves, so that when he talks back, he forfeits one of those things.
This has to be individualized to each child, but if you can find a number of them, write them down in a list, and link each one to either the severity of the back talking, or the frequency, it could work. Putting things on poster board on the fridge works as a constant reminder around our house.
On the flip side, you might want to create a poster to reward him when he shows respect and responds/answers "correctly" (depending on the situation). You can award stars on the poster for each one, and work out a larger reward (ice cream or a trip to a favorite place, maybe) when he's earned, say, 50 stars. This will reinforce good behavior, rather than only focusing on the bad. If this is going on at school, you might want to take a sheet to school for the teacher to record "stars" and "minuses" to record at home.