  For a general class of $N$-body Schr\"odinger operators with short-range
pair-potentials the wave and scattering matrices as well as the restricted wave
operators are all defined at any non-threshold energy. This holds without
imposing any a priori decay condition on channel eigenstates and even for
models including long-range potentials of Derezi\'nski-Enss type. In this paper
we improve for short-range models on the known weak continuity properties in
that we show that all non-threshold energies are stationary complete, resolving
in this case a conjecture from [Sk1]. A consequence is that the above
scattering quantities depend strongly continuously on the energy parameter at
all non-threshold energies (improving on previously almost everywhere proven
properties). Another consequence is that the scattering matrix is unitary at
any such energy. As a side result we obtain a new and purely stationary proof
of asymptotic completeness for $N$-body short-range systems.
