Epistle to the Romans Theme of Transformation

Paul is really big on change. According to the letter-writing man himself, Christians become totally new people when they put their faith in Jesus. They die to their old lives. They die to sin. They become like happy, fresh, new babies out there in the world. But as humans, we know that change ain't easy.

1. Why is transformation so important for Paul? What do Christians get when they live "in Christ?"
2. According to Paul, if you die to sin, does that mean you can never, ever sin again?
3. How does Paul's advice in 12:2 not to conform to the world jive with his advice to obey authority in Chapter 13?