Software product line engineering aims at producing functionally similar software systems as a family of products. In this process, the development life cycle has been shifted from traditional activities into reusecentric and customizable component approaches. In software product line engineering from existing systems many technical, organizational, and user-adoption problems need to be dealt with by the means of proper tool support. In this context, we provide a supporting toolkit that blends the behavior and structure recovery techniques in order to localize the major components of the existing systems as candidates for generic or reusable components. An integration of the reusable and new components will form a domain reference architecture, whose instantiation will produce the products. For each new product the scattering of the added features in the structure of the original components will be determined by the means of two metrics to assess the functional cohesion and feature functional scattering. This allows us to control the structural evolution of the product line engineering process.