This is the GT3 tuning section. Once you're on this page, do an advanced search...typing in Mazda 787B and Mazda RX7. You can even narrow the search down to GT3 tuning, or broaden it to the entire GT3 section.
You can also use this search to search for titles only, or include references to various posts including info on the RX7 and 787B. There's A LOT of info to navigate here.