  We carry out a dynamical analysis of first order perturbations for Cold Dark
Matter, $\Lambda$ Cold Dark Matter, and a couple of Modified Gravity models
using the Parametrized Post-Friedmann formalism. We use normalized variables to
set the proper dynamical system of equations through which we make the analysis
in order to shed some light on the dynamics of such perturbations inside these
models. For Modified Gravity models, we use the scale-independent and
-dependent parametrizations, in particular, two $f(R)$ and two Chameleon-like
models are considered within the quasi-static approximation. Given the employed
formalism, we found that the critical points and stability features of the
dynamical systems for Modified Gravity models are the same as those found in
the standard $\Lambda$ Cold Dark Matter model. However, the behavior around the
critical points suffers important modifications in some specific cases. We
explicitly find that signatures of these Modified Gravity models mainly arise
on the velocity perturbations, while the density contrast and the curvature
potentials turn out to be less sensitive to the parametrization taken into
consideration. We also provide a percentage estimation of the extent of
modification in the perturbations in the Modified Gravity models considered in
comparison to the standard $\Lambda$ Cold Dark Matter model along the expansion
history and for a couple of wavenumbers.
