  We present our recent progress on the relativistic modeling of
electron-nucleus reactions and compare our predictions with inclusive $^{12}$C
($e,e'$) experimental data in a wide kinematical region. The model, originally
based on the superscaling phenomenon shown by electron-nucleus scattering data,
has recently been improved through the inclusion of Relativistic Mean Field
theory effects that take into account the enhancement of the transverse scaling
function compared with its longitudinal counterpart. We also discuss the impact
of meson-exchange currents (MEC) through the analysis of two-particle two-hole
longitudinal and transverse contributions to electromagnetic response functions
evaluated within the framework of the relativistic Fermi gas. The formalism is
also extended to include the complete inelastic spectrum -- resonant,
non-resonant and deep inelastic scattering (DIS). The results show quite good
agreement with data over the whole range of energy transfer, including the dip
region between the quasielastic peak and the $\Delta$ resonance.
