The precise determination of global properties of galaxy clusters, and their scaling relations, is a task of prime importance for the use of clusters as cosmological probes. We performed a detailed XMM-Newton study of 14 X-ray luminous REFLEX Survey clusters at z∼0.3. We found that the properties of the galaxy clusters show a self-similar behavior at r>0.1r vir . This helps us to establish tighter scaling relations. Peculiarities in the individual clusters are important to understand the scatter from the self-similar frame in the cluster central parts.