  The paramagnetic phase of the extended attractive Hubbard model on the cubic
lattice is studied within the spin rotation invariant Kotliar-Ruckenstein
slave-boson representation at zero temperature. It is obtained that the
quasiparticle residue of the Fermi liquid phase vanishes for all densities at
an interaction strength slightly smaller than $U_c$ that signals the
Brinkman-Rice transition, and that it weakly depends on density. While for
vanishing non-local interaction parameters homogeneous static charge
instabilities are found in a rather narrow window centered around quarter
filling and $U \simeq 0.8\ U_c$, increasing them to $V = -0.2\ U$ results into
a severe narrowing of this window. On the contrary, when all interaction
parameters are attractive, for example for $V = 0.2\ U$, a large parameter
range in which homogeneous static charge instabilities is found. Yet, this
systematically happens inside the Fermi liquid phase.
