"The Revolutionary Guards Will Do Anything to Keep Khamenei in Power."
Don't bet on it. The Revolutionary Guards are tasked with protecting the legacy of the 1979 Islamic Revolution and its embodiment in the vali-e-faqih, the supreme leader, currently Ayatollah Ali Khamenei.
The Guard's top leaders are military men who have served many years in the ranks and as such are unlikely to disobey the orders of their commander in chief. Their view, as they have expressed repeatedly in public fora, is that the green movement and its leaders are a threat to the revolution and to the supreme leader. But they are probably more concerned with protecting the position of the leader (and their own power and pervasive influence in Iranian business and politics) than they are in protecting a particular individual.
There are many former top commanders of the Guards, such as Mohsen Rezai (a defeated candidate in the presidential election), Mohammad Qalibaf (Tehran's popular mayor), and Ali Larijani (speaker of the parliament), who oppose Ahmadinejad (and have influence with the Guards), but have not so far challenged the supreme leader. That doesn't mean, though, that they would not look to replace Khamenei should it become apparent that he is an obstacle to the regime's stability. Although any moves against the supreme leader are highly unlikely at this point (and he still has the support of the majority of the members of the Assembly of Experts, the body that elects, monitors, and can even impeach him), that doesn't mean that such a challenge could never happen.