Actually I have to agree with G-Man and with Michael. Usually the team that races better gets 2nd, with a few exceptions. Reichen & Chip were the first team to win that actually had the best average performance in a season the next time that happened was season 10's Tyler & James.
But usually that typical race well do win (just not usually the best).
You can be a rather poor racing team and as long as you aren't last (or are saved by non elimination or multiple non eliminations yeah Flo & Zach and BJ & Tyler I am talking about you), all you really need to is run an ok final leg, and typically do well once you reach the destination city.
To keep the possibility of a photo finish they try and assure that all teams are equalized far more then in a typical leg making it anyones game.
As to the edit, of Jenn & Nathan. I don't think they were edited in a positive light this last episode, I think they were just much more positive. Even in clips they never lose it even when frustrated with being lost. And this does happen. Now obviously they could have been doing a smackdown on each other and never make the aired footage or the online material (nature of the program), but I don't believe this was the case in this episode. Usually when they are doing well and not having big problems they tend to get along much better. Now if they had gotten passed, by other teams I would imagine the stress to get far greater and see more frustration and anger. This episode was much closer to episode #2, 3, and 4 where they typical were in or near the front of the pack. Episode 1 when they went from 2nd to having no luck (or skill with animals) to next to last, hell yes tempers were up. Episode 5, when they go from front of the pack to mid pack and have trouble with navigation and with tasks the anger and frustration comes out. In #6, while they were in near the front of the pack they didn't know it, they didn't know where the other teams were. And this seems to be a team when they have problems they fight.. When things go well, they usually are pretty descent to each other.
I think India might be a huge shock for them....he, he.
India is great for that.