There’s little information about this car readily available in English, but as far as I understand Top Secret had a team running in Super Taikyu back in 2002-2004. Super Taikyu is an endurance race set in Japan similar to Super GT but with more commercially-available cars. The race is divided into different classes, and this DC5 was racing in the ST-4 class. Top Secret had made two different versions of the car, the regulation spec competition car and a high-output turbo demo car. Most of the parts used on the cars are prototypes, meaning they likely tested the parts on the track before selling them for customer cars. From what I've gathered, it looks like the competition-spec car wasn't focused on making more power, but on increasing the responsiveness of the engine with the VTEC capabilities. It had an original KA20 with an HKS F-Con V Pro ECU installed. A few details I've been able to gather are the Aragosta adjustable suspension, adjustable wing (depending on the iteration of the car), Top Secret front bumper, Advan A048 S tires, Rays CE28 wheels (for at least one of the cars), and a titanium exhaust. This is info is from just one of the cars, as it seems that over the years the car had evolved with different wheels and components, such as the carbon fiber hood. I assume the more simple livery design is 2002, the wave looking design is 2003, and the more complex design is 2004.