To make the CGI cars seem less akward around the animated characters, the cars in Fourth Stage have been given a softer 'cel-shaded' look to help them blend in.
Takumi's first adversary in Fourth Stage is a red Mazda Eunos (Miata in U.S.). This will make for the first non-RX-7 Mazda in the series' history.
In episode 10, Takumi races against a Suzuki Cappuccino, a small car that falls into the Japanese keijidousa, or 'K-Class'. K-Class cars can be built no longer than 4.4m (14.4 feet), no wider than 1.5m (4.9 feet) and equipped with an engine no larger than 660cc that has to produce less than 64bhp (although superchargers or turbochargers may be added). K-Class have lower taxes, cheaper maintenance, comparatively simple registration and are very popular in Japan. Surprisingly, the Cappuccino is the first use of a K-Class car in the series.