Chassis bracing for STX build - 2019 BRZ

[N_Raged]

Hello, What are the recommended chassis upgrades for STX class? I have STi tS springs, adjustable Tein Endurapro dampers, a front swaybar, and will have major front and rear camber mods.


I'm having trouble interpreting the SCCA rules around bracing:

14.2
G. Strut bars per Section 12 are permitted with all types of suspension, subject to the following constraints:

1. A 2-point strut bar may be added, removed, modified, or substituted, but only with another 2-point strut bar.

2. A triangulated (3-point) strut bar may be removed, modified, or substituted; substitution may be with either a triangulated or a 2-point strut bar. The connection to the chassis (e.g., firewall, bulkhead) must be in the standard location.

3. Lower suspension braces must be attached to the lower suspension pickup point locations on the chassis within 2" (50.8mm) in any direction of the actual suspension attachment to the chassis.

4. Except for standard parts, no connections to other components are permitted. Additional holes may be drilled for mounting bolts. Only "bolt-on" attachment is permitted. Interior trim panels may be modified to allow installation of strut bars. Holes or slots may be no larger than necessary and may serve no other purpose. This does not permit any modifications to the frame or unibody beyond the allowed mounting holes.

H. Longitudinal (fore-aft) subframe connectors ("SFCs") are permitted with the following restrictions:

1. They must only connect previously unconnected boxed frame rails on unibody vehicles.

2. Each SFC must attach at no more than 3 points on the unibody (e.g., front, rear, and one point in between such as a seat mount brace or rocker box brace).

3. SFCs must be bolted in place and not welded.

4. No cutting of OE subframes or floorpan stampings is permitted. Drilling is permitted for mounting bolts only.

5. No cross-car/lateral/triangulated connections directly between the driver’s side and passenger’s side SFCs are permitted. Connections to OE components such as tunnel braces or closure panels via bolts are allowed and count as the third point of attachment. No alteration to the OE components is permitted.

When it comes to underbody bracing, what can I do or cannot do for STX? For example looking at the TRD member brace set, or the various Cusco underbody braces, which pieces are allowed?

The rules around strut bars is clear. My car already has a stable front end thanks to the front sway bar so I don't think I would want a front tower bar to potentially add more understeer. My rear on the other hand is a bit snappy and I can get into a tank slapper sometimes from really abrupt transitions - would a rear tower bar help here? Or should I prioritize Whiteline rear subframe inserts or even a rear sway bar?

Anything else I should be considering?

[whataboutbob]

I'd be looking at steering inputs, tire choice, tire pressure, and rear swaybar first.

[DocWalt]

None of those braces are going to do anything worthwhile.

[N_Raged]

Okay will stick to rear subframe inserts and rear sway bar then.
Thank you all.