The 2010 new regulation standards were established to prevent the noise of cars and motorcycles on the public streets. The inspection bureau authorized by the Ministry of Land, Infrastructure, and Transport is supposed to measure the noise level within the close area and the noise level by acceleration, certify the exhaust system, and give it an official sign. In case you replace the exhaust system of the subject vehicles of the 2010 new regulation standards with the different exhaust system, you are required to newly have the different muffler certified and get an official sign. Otherwise,
the vehicles do not meet the official car inspection.         
As for the details of the 2010 new regulation standards, please refer to the documents drafted by the Ministry of Land, Infrastructure, and Transport and JATA (a legally incorporated foundation: JAPAN AUTOMOBILE TRANSPORT TECHNOLOGY ASSOCIATION).

the official website of the Ministry of Land, Infrastructure, and Transport →http://www.mlit.go.jp/unyuanzen/index.html
the official website of JATA→http://www.ataj.or.jp/index.html

※The subject vehicles of the 2010 new regulation standards are described as the vehicles equipped with the exhaust system adaptable to the regulation standards of acceleration run in the notes of the car inspection certificate.

Also, please bear in mind that the manufacturers are required to get an official certificate of ISO9001 or adopt the same quality control system as ISO9001.
  The authority has already recognized that TOMMYKAIRA JAPAN has the same level of ISO9001 as to the inspection of our products and every material we are supposed to use, and our quality control system etc.

the kind of vehiclesthe kind of vehicles	typetype	grade	certification
TOYOTA
PRIUS	ZVW30	all grades	already certified
ALPHARD	GGH2#	all grades	scheduled to apply
VELLFIRE	ANH2#	all grades	scheduled to apply
NISSAN
ELGRAND	E52	all grades	already certified
HONDA
STEP WGN SPADA	RK5		already certified
STEP WGN SPADA	RK6		already certified
SUBARU
LEGACY	BR9/BM9	TurboE-5AT	already certified
Audi
Audi A5	8TCDNL	SPORTBACK	already certified
Audi A4	8KCDNF	A4,A4 AVANT	already certified