Midway through the 2007 D1 series Kumakubo switched from the Impreza to an Evo 9 (built also by JUN Auto) during round 5 at Ebisu.

He has also built a Mitsubishi Lancer Evolution X in the Team Orange livery which was shown at the Tokyo Auto Salon.

He also runs the Big X the invitation only outdoor show that combines drifting, FMX, supermoto, car stunts and other extreme sports featuring the experts from each field.

Big X's drifting squad is called DriftXtreme, which the well known drivers of the D1GP are invited to join including team mate Kazuhiro Tanaka and Naoto Suenaga.

Kumakubo competed in the European Drift Championship during the 2008 season alongside his Team Orange teammate Kazuhiro Tanaka in his Subaru Impreza WRX STI.