*What is JARI certificated…

JARI stands for the Japan Automotive Research Institute. It is an organization involved in various activities related to automotive research, testing, and certification in Japan. JARI collaborates with industry partners, government agencies, and international organizations to promote advancements in automotive engineering, safety standards, environmental regulations, emissions reduction, and energy conservation.

One of the areas where JARI is involved is in testing vehicles to ensure compliance with Japanese vehicle inspection standards. This includes assessing factors such as exhaust note volume limits, which are part of the inspection process. Vehicles need to meet these volume limits to pass the inspections.

*In the case of the GR SUPRA 3.0L exhaust, you mentioned that there are different part numbers (31029-AT003, 31029-AT007, and 31029-AT008), but they represent the same physical product. It's possible that these different part numbers correspond to variants of the exhaust system that have been certified by JARI for compliance with Japanese exhaust regulations. The reason for having different part numbers for the same product could be related to tracking and identification purposes, including differentiation for specific regulatory requirements or applications within the Japanese market.