Bones: Jim, you just sat that man down at a high-stakes poker game with no cards and told him to bluff. Now, Sulu's a good man, but he's no captain.
James T. Kirk: For the next two hours, he is. And enough with the metaphors, all right? That's an order.
At one point Khan threatens to target the Enterprise's life support systems which are located behind her "aft nacelle". The Enterprise doesn't have an aft nacelle; as the many exterior shots show, it has a port nacelle and a starboard nacelle. Khan a) is familiar enough with Starfleet ships to know this basic fact about the Enterprise, and b) can see its nacelles for himself on his own viewscreen while he's delivering this line. There is no "nacelle" housing the impulse engines. They are enclosed by the hull of the saucer section.
As Kirk, Spock, and Uhura head to the shuttle bay for their mission to Kronos to capture Khan, Sulu orders crew to prepare the vessel that was confiscated in the Mudd incident. This is a reference to Harry Mudd, a roguish character who appeared in the original Star Trek series in the episodes titled,"I, Mudd" and "Mudd's Women." Harry Mudd, played by Roger C. Carmel, was the only non-regular character to appear in more than one episode on the original Star Trek series. Carmel was slated to reprise the role in Star Trek: TNG, but he died before the episode could be filmed.