  We investigate dark matter halo properties as a function of a time--varying
dark energy equation of state. The dynamics of the collapse of the halo is
governed by the form of the quintessence potential, the time evolution of its
equation of state, the initial conditions of the field and its homogeneity
nature in the highly non--linear regime. These have a direct impact on the
turnaround, virialisation and collapse times, altering in consequence the
non--linear density contrast and virial radius. We compute halo concentrations
using the Eke, Navarro & Steinmetz algorithm, examining two extreme scenarios:
first, we assume that the quintessence field does not exhibit fluctuations on
cluster scales and below - homogeneous fluid; second, we assume that the field
inside the overdensity collapses along with the dark matter - inhomogeneous
fluid. The Eke, Navarro & Steinmetz prescription reveals, in general, higher
halo concentrations in inhomogeneous dark energy models than in their
homogeneous equivalents. Halo concentrations appear to be controlled by both
changes in formation epochs of the halo cores as well as by differing
virialisation overdensities. We derive physical halo properties in all models
and discuss their observational implications. We examine two possible methods
for comparing observations with theoretical predictions. The first method works
on galaxy cluster scales and consists of fitting the observed X-ray cluster gas
density distributions to those predicted for an NFW profile. The second method
works on galaxy scales and involves the observational measurement of the
so--called central density parameter.
