Sidewinder

Sidewinder (サイドワインダー Saidowaindā) is a highly skilled team that organized the "4 lines of defense". Their home course is the Tsubaki Line, but the nearby Toyo Turnpike may be a part of their home territory (Ryosuke's battle with Rin Hojo was raced there). There are many rumors that they might be the "fourth line" or the last team in Kanagawa that Project D will compete with. In the storyline, this team is trying to analyze Project D's weaknesses. They collect information by watching Project D during their practices and races.

Go Hojo
Go Hojo (北条 豪 Hōjō Gō? ) is the Chief Driver of this team. He seems to know Ryosuke Takahashi quite well, despite not having any past connections or quarrels with Ryosuke. Instead, he knows him through his elder brother, Rin, alluding to a girl named Kaori.

Go helps the chief mechanic of Sidewinder named Eiji Kubo to evaluate Project D's weaknesses. He loses the race after spinning out while chasing Keisuke due to wearing out his rear tires.

Shinji Inui
Shinji Inui (乾 信司 Inui Shinji? ) makes his debut during Project D's battle against Team Spiral. Shinji is a member of Sidewinder and therefore second driver of this team. Shinji appears to be a boy (possibly younger than Takumi) but seems very intelligent. Shinji's car is the notchback coupe variant of the AE86 Trueno (not to be confused with Takumi's Eight-Six). He is the fourth character to drive a Toyota AE86 model, after the fake Takumi's Trueno AE86. Shinji lost to Takumi, due to both cars spinning out. With the tires of Takumi's 86 locking up, it sent Takumi's 86 into a spin. Shinji had no choice but to follow. At this moment, with the experience gained from the engine blow in Akagi when going against the Evo III, Takumi instinctively presses on the clutch, freeing up the tires and regained control of the 86 momentarily. However, Takumi was going in reverse with inertia alone. Shinji, on the other hand, lacked actual dogfight experience and didn't know what to do, spinning a full 360 degree, causing him to lose more momentum than Takumi did. Takumi won by crossing the finish line backwards with his 86. Shinji's 86 ended up facing the finish line after the 360 spin. After the race in Final Stage, Shinji apologized to Hojo, Kubo, and his mother that he wasn't able to win for them. But they're weren't angry at him at all, and said that he had done enough for the team and glad that he returned safely after the fierce battle.

Rin Hojo
Rin Hojo (北条 凛 Hōjō Rin? ), known as "Shinigami", is Go Hojo's elder brother and a legendary driver of Kanagawa. Rin has had a long-standing feud with Ryosuke because of a girl named Kaori, who was the former's arranged fiancee at the time. Kaori would commit suicide after Rin verbally abuses her, claiming that she'll regret rejecting him when she and her family will be ruined. After this event, Rin left the racing scene and became a recluse, locking himself in his home for years, before making a surprising return and racing (unofficially) against Team Spiral's leader, Ikeda. Rin is an extremely skilled driver who utilizes a dangerous driving style.

He races against Ryosuke so as to make him pay for a past incident involving Kaori by trying to push him off the road. This severely backfires as Ryosuke manages to shake off Rin's attacks, resulting on serious brake problems on his GT-R. Rin decides to do a "kamikaze" as his last final attack on Ryosuke. To prevent him and Ryosuke from crashing at a toll booth, both Ryosuke and Ikeda (who had been spectating from behind) use their cars to buffer Rin's BNR32 to slow it down. Kaori's presence was felt by both Ryosuke and Rin during the attempt. Fortunately, Rin's car was indeed stopped and the whole race managed to bring closure of Kaori's death to Rin. He knew Ryosuke felt his pain.

Eiji Kubo
Eiji Kubo (久保 英次 Kubo Eiji? ) is the Chief Mechanic of Sidewinder. Kubo appears to have a high amount of knowledge about a car's performance and capabilities as well as race theories. He can make very precise anticipations as he did during Project D races against Team 246. As seen in the manga, Kubo has been entrusted to analyze and evaluate Project D's weaknesses.