  Tree level unitarity violations of extra dimensional extensions of the
Standard Model may become much stronger when the scalar sector is included in
the bulk. This effect occurs when the couplings are not suppressed for larger
Kaluza-Klein levels, and could have relevant consequences for the phenomenology
of the next generation of colliders. We briefly review our formalism to obtain
more stringent unitarity bounds when KK modes are present, as well as the
generalization to extra dimensions of the Equivalence Theorem between Goldstone
bosons and longitudinal gauge bosons
