Dueling Dubs: The movie was dubbed twice into English by two different companies (Streamline and Manga UK), both in 1995, and with two completely different voice casts. The UK dub also replaced the entire musical score with licensed music from Yello. Also, despite Streamline's reputation for more liberal dubs, their dub for Cobra is actually quite a bit more faithful than Manga UK's, which took a lot of cues from the French dub.
The Other Darrin: In the Japanese version, most of the characters' voices were recast between the movie and TV series. The recent seasons also have different voices for the characters.
No Export for You: For the longest time, only the movie was imported to English-speaking territories, though attempts were made to bring the TV show over. TMS created a pilot for the US market in 1983 written and directed by John Semper Jr that mixed existing animation with original animation, but it was never picked up. Streamline licensed it in the late 90s, and after dubbing and releasing the movie in theaters, planned on dubbing the show with their movie cast, but their distributor, Orion Pictures, ran into financial problems and couldn't release the show or the movie on home video. The movie was released to VHS by Urban Vision in 1998, but it wasn't until 2014 that the TV series saw a release in English. Today the franchise is divided up between three companies: Discotek Media (movie), Right Stuf/Nozomi Entertainment (TV series), and Sentai Filmworks (sequel series/OVA).
The manga was licensed by Viz Communications in the early 90s, but they only released a few issues. Reading the entire manga in English requires scanlations.