The Fosstech cage design is a combination of mine and the one below, plus with the addition of items like integrated air jacks, seat mount bars and a few additional strengthening points:
As promised, here’s some detailed pictures of the cage and how the dash was cut. The last two (yellow) pictures are of the gusseted bar that goes through the front shock tower beam (hidden from plain view).
Also here’s another example from my other racecar (white ’98 ITR):
