My guess is that US intelligence has several "shadow" arms that have morphed into their own creatures and are no longer the same patriotic beast it was during the cold war. I'm doubtful whether destabilizing China is a real possibility, in the "CIA in Latin America" sense.

This is a quite short-sighted point of view. The real challenge is to establish a stable new regime after toppling the old one. In the case of mainland China that has no prior experience at all as a democratic society, it would have a difficult time adapting (PRC before WWII doesn't count since it was unstable and higly corrupt). Also, a weak goverment is in danger of neglecting to address the internal challenges China faces (tensions with minorities, poverty in rural regions, environmental destruction).