Miki also competed in the Net'z Cup, a one make series for the Toyota Altezza between 2005 and its final season in 2006[1][2][failed verification] and is nicknamed Doki-Doki kun due to his drifting style.

For the 2005 season, following the opening Irwindale round, Miki switched to a Top Secret modified Fairlady Z Z33 powered by a RB26.

Much of it was, at the time, the Z33 was still in development to be fully competitive in drifting, due to its weight, one of its reason why it befell many of its drivers.

For the 2006 season, rival Youichi Imamura's team and title sponsor, A'PEXi withdrew from the series due to a redirection in the company's business strategies, leading him to take over Miki's Z33.

Reaching the rank of top 16 within 4 events, Ryuji finally adapted to the car within the 6th and 7th rounds finishing 14th overall for the season.