  We present preliminary results on galactic Dark Matter (DM), halo structure,
and galaxy evolution. We show how during the first Gyr of the evolution of a
$10^{10} M_{\odot}$ dwarf elliptica feed-back from stars (SN\ae~ and stellar
winds) leads to an extended constant density isothermal core with radius of
0.15 the virial radius $R_{200}$. We also present first results on galaxy
merging as a possibile scenario to form ellipticals, studying in particular how
the details of the merging evolution vary as a function of the mass ratio of
the interacting galaxies.
