  Specific quasi-realistic superstring constructions often predict the
existence of new TeV-scale physics which may be different in character from
bottom-up motivated constructions. I describe examples of such beyond the MSSM
physics, with special emphasis on heavy Z' gauge bosons and associated exotic
particles. Implications of an extra U(1)' include a viable scienario for
electroweak baryogenesis, a highly non-standard light Higgs sector, and
Z'-mediated contributions to rare B decays.
