Outstanding job Scott- IMO the classing is easier to read and apply than it was before, but makes the classing make much more sense once we see who goes where in grids. Kudos.
Oh, and damn am I lucky. Curb weight is listed for a 1996 Miata as either 2293 or 2312 pounds depending on which websites you belive. Owner's manual doesn't list curb weight, only GVWR.
Anwyays, with seat swap, DOHC, and 16 valves, if it weighed 2283 or less, it would be TT-4 instead of TT-5.
Lucky me! And Russ Carpenter I guess. Ha.