Hmmm... maybe that last section covers it, although I'm not sure what that is actually saying
.
FWIW, structurally I don't think the mounts benefit much from those stiffeners, at least not with the loads that the small-ish BRZ bars will exert on them. The STI requires a much larger rear bar and a larger bar/spring roll stiffness ratio, and I never had any issues with the mounts. I believe those braces came about on the legacy that initially had that multilink rear design, and with that chassis the swaybar mounts were much thinner and did tend to bend (according to Myles at @
Racecomp Engineering). But I think when Subaru adapted that suspension to the Imprezas they strengthened them quite a bit.
(and not trying to be a pain just wanted to bring it up since you plan to run national events with it - definitely would not want to run into issues over something small like that
)