I doubt that there is any sort of merger planned, if the new District Superior of the FSSP has anything to do with it, since he held very anti-SSPX views six years ago (thinking that they were a cult). He never preached these views openly, but told them to an SSPX chapel attender that I knew back then, who attended a few FSSP Masses, and had a few long conversations with him after Mass. Maybe he has since then relaxed his views of the SSPX. I doubt it though.