Companies can use methodological software tools to perform requirement engineering. Those methodological tools are increasingly developped by external software editors and integrators. The performance of the tools is not enough to ensure efficiency of methodology application. This paper is part of a PhD research program. This research program focuses on the way of integrating requirement engineering tools into product design department with a provider perspective. To be more precise, this research project emphasizes on modifications occuring during integration phases. In order to evaluate and improve integration process, key indicators can be proposed. From the first stage of integration to the moment user is autonomous, key integration factors often change. For example, requirements of the user, user environment, product life cycle, delay integration, actors, ... This paper aims at proposing surveys to identify those changing key factors. Then, first best practices elements are given to counteract the possible negative impact on efficiency of requirement engineering tools integration and thus, on product development. In fact, this paper goes further into the way to analyze existing system. It notably deals with first elements from industrial survey on IT vendor and their customer perspectives on tools integration. In addition, preliminary survey results on customer dissatisfaction are proposed and analyzed. It also proposes a short case study and further research work in order to assume those first results and to bring to the definition of integration approach for methodological tools in engineering domain.< Réduire