Monroville said:

On another note, I can't say I ever cared for the Vader line: "How is that possible?" I liked how in the original dialogue Vader is making statements to counter the Emperor's, as well as talking the Emperor into doing things his way. The "How is it possible?" line kinda comes across as Vader is a little stupid.. you know, like how he is in JEDI.

I hate the line too, but here is a take that might make it a little easier to stomach.

cap said:

Oh, I get it now.

EMPEROR: We have a new enemy, the young Rebel who destroyed the Death Star. I have no doubt this boy is the offspring of Anakin Skywalker.
VADER: How is that possible? Anakin Skywalker has no offspring.

VADER: How is that possible? He was living on the planet farthest from the bright center of the universe, Owen and Beru were keeping him down on the farm, he knew nothing of the world around him and had never even heard of the Force. Then within two days he had come out of nowhere, showcased Jedi skills, and forever changed the course of Galactic history by DESTROYING THE FREAKING DEATH STAR!!! How the fuck did that happen to us?!!

EMPEROR: He could destroy us.

VADER: He’s just a boy. Obi-wan can no longer help him.

See? Makes much more sense now.