The European XFEL [1] bunch compressor system has been optimized for greater flexibility in parameter space. Operation beyond the XFEL design parameters is discussed in two directions: achieving the uppermost number of photons in a single pulse on one hand and reaching the necessary peak current for lasing with a pulse as short as possible on the other. Results of simulation calculations including 3D-CSR effects, space charge forces and the impact of wake fields demonstrate the potential of the XFEL for further improvement or, respectively, its safety margin for operation at design values.
