  At the LHC, it will be possible to investigate scenarios for physics beyond
the Standard Model in detail. We present precise total and differential cross
section predictions, based on Prospino2.0 and SMadGraph. We also show to what
degree the structure of the weak--scale supersymmetric Lagrangean can be
studied, based on LHC data alone or based on combined LHC and linear collider.
Using Sfitter we correctly take into account experimental and theoretical
errors. We make the case that a proper treatment of the error propagation is
crucial for any analysis of this kind.
