Munnich, who is a four-time German rallycross champion, said that he was using the drive to evaluate a possible switch to the series for his team in 2013.
"It is a good opportunity for me to evaluate the WTCC," he said. "As a driver this is a new challenge for me. I have never raced at Suzuka before.
"Luckily we are using the short circuit so that will give me the chance to learn the track quickly and get used to the car.
"Competition in the WTCC is of the highest level, so it will take some time to get used to it. And I also want to use this time to investigate the possibility for our team to join the championship next year."
Other driver news includes the confirmation that China Dragon Racing will field three Chevrolet Lacettis for Felipe de Souza, Ng Kin Veng and Celio Alves Dias at Macau.
Team Engstler will run a third BMW for Jo Merszei while Mak Ka Lok and Henry Ho will race privateer examples. Eurico de Jesus will drive an ex-JAS Motorsport Honda Accord.
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The 2012 World Touring Car champion says he never had the money to race cars. Yet 2015 is his 11th season in the WTCC. He talks STUART CODLING through his journey from motorsport fan to paid professional - for little more than £100,000