  Redshift distortions, both geometrical and kinematical, of quasar clustering
are simulated, for the Two-Degree Field QSO Redshift Survey (2QZ), showing that
they are very effective to constrain the cosmological density and equation of
state parameters, Omega_{m0}, Omega_{x0} and w. Particularly, it emerges that,
for the cosmological constant case, the test is especially sensitive to the
difference Omega_{m0} - Omega_{Lambda 0}, whereas, for the spatially flat case,
it is quite competitive with future supernova and galaxy count tests, besides
being complimentary to them.
