Since increased chassis rigidity is always good -- especially considering we have greatly increased the suspension loads with the stiffer coilovers -- we applied Cusco chassis braces to the front of the STI. Underneath the engine, we bolted up a Lower Arm Bar, which ties together some of the front subframe bits, and replaces a thin steel reinforcement plate (that's the triangle shaped part) with one that's made from material that's twice as thick. If you know Cusco parts, you might notice that the Lower Arm Bar is gold -- this particular part was sold under Cusco's now-retired "Vacanza" brand. All the parts in that line were finished in gold instead of the usual Cusco metallic blue.
Up under the hood, we applied a Cusco OS upper strut bar. It only took a few minutes to install it. It looks like the bar leaves plenty of room for a larger intercooler, should we choose to add one later.
Cusco has not yet released rear chassis bracing for the 2008+ STI, but when they do, we'll be installing those, too.