The suspension on your Miata is cantilevered out from the front bulkhead. These braces reinforce the frame horns that support the engine and transfer all of the cornering and road impact loads into the rest of the chassis. This means that you'll get less flexing and cowl shake, especially when running stiff springs and/or high torque engines.
Frog Arms were the first product that worked along these lines, but they're no longer available. We took that as an opportunity to improve the design and increase the stiffness without changing the price. We extended the arms further forward and added a third dimension to the shape for maximum rigidity. Clever design keeps the weight to a minimum - only 6 lbs per side. Made of High Strength Low Alloy steel.
Sold in pairs. Simple bolt-on installation. Fits NA and NB Miatas. Available both in bare steel or black powdercoat for $30 more. The bare steel is not coated in any way and will need to be painted or coated.
As it sits behind the shock tower brace, it should not adversely affect crumple zone performance.