Some of the events in the series do happen in Real Life in regards to Formula racing. Some examples:
In the first episode of Zero, (released in April 1994) Hayato suffered severe injuries after he was involved in a huge crash with Randoll and his car went off the track banking. One month later, similar incidents happened at the 1994 San Marino Grand Prix where two separate crashes took the lives of Roland Ratzenberger and 3-time F1 champion Ayrton Senna.
The friendly rivalry between Hayato and Kaga references the 1976 Formula One season, in which then-defending champion Niki Lauda (Austrian, driving for Ferrari) and his biggest friend and rival James Hunt (British, driving for McLaren), fought until the very end of the season. The finale of Sin is also possibly influenced by the 1976 season finale, as James Hunt won the title at the very last race in Japan. This outcome might have influenced Kaga's last-minute championship victory at the end of the OVA.
The AKF code name used in later models of the Super Asurada is derived from the initials of Asurada (car), Kazami (original designer, Hiroyuki Kazami or driver, Hayato Kazami), and Fortran (designer). In the Sin OVA series, most of the Sugo car models (including the AKF) also included the initial G for Sugo's new engine manufacture/sponsor Gio.
In episodes 29 and 30 of the TV series, the 1991 Mitsubishi HSR-III concept car appeared under cooperation by Mitsubishi Motors. It was different from the real concept car, the car was set as a driverless car that can talk.
The name of "Knight Schumacher" (seen spelled as "Shoemach" in the series) is in reference to Michael Schumacher who won the Formula Three German championship in 1990. The reason for the name was because it seemed to be a fitting name for a fast driver. The staff was rather surprised when they learned that Michael Schumacher debuted in Formula One racing that same year in 1991. For this reason, Knight Schumacher wears the racing suit of Benetton Formula in the final episode of the TV series. Additionally in a case of life imitating art, Knight Schumacher during his second season used numerous 'dirty' tricks and tactics; something Michael Schumacher would later be accused of several years later.
Anime First: There are a number of novels and manga that have been released over the years.
Due to poor sales of the US DVD brick set of the TV series (probably due to its hefty price tag and the series' obscurity within the States), it's highly unlikely that the OVA sequels will ever the see light of day in the US. This also includes the games and drama CD's based on the series.
So far, only the SNES game based on the TV series was released in the US, but the references of the anime were mostly removed.
Junichi Kanemaru, Hayato's seiyuu, also played as V8. Yes, you heard right. He also played as a dog.
Bin Shimada played both Gudelhian and Hiyoshi, Nobutoshi Canna played Leon and Katagiri, Naoki Tatsuta voiced Bootsvorz and Ryohei (in Saga), Yuri Amano played Kyoko and Satsuki and so on... In fact, in the final episode of ZERO, Gudelhian and Hiyoshi (both voiced by Shimada) have a conversation after they were out of the race.
Technology Marches On: For a series taking place in the 21st century in which race cars relying on new technologies, some of the characters use 80's-style cell phones and computers use floppy disks to read data. These things may be in vogue in 1991, but not so much today.
According to the Japanese version of the Other Wiki, the staff of the TV series originally wanted to make a Speed Racer type of show, but the "F1 Boom" in Japan happened at the time during the stages of production, and this is what it eventually became of the series.
The TV series was originally planned for 50 episodes, but terrible TV ratings, along with a sales slump of merchandise and a sponsorship drop from Takara led to it being cut down to just 37. However, fans loved it so much that four OVA sequels were made.