I agree that Sawyer was trying to size up the fighting ability of the others, but that seeing Kate look so spent didn't hurt his manly urges any either!
The way that Sawyer keeps looking at Juliet makes me wonder if they know each other. The way she called him James, and Kate asking about it, seems to me like they are trying to make a point. Although I know they KNOW everyone's names anyway...
Was the kiss somehow also intended to get a rise out of Juliet?