The Banshee 900R, one of GTA Online's recently added cars, has apparently received a slight speed buff.
Rockstar promised that an upgraded Banshee will be as fast as a Zentorno or a T20. However, the community later realised this was not the case. It seems Rockstar corrected this issue, without actually tweaking game code.
That's according to YouTuber Broughy1322, who's tested the Banshee recently and found that it's faster in a straight line. In fact, it's now the game's fastest car in a straight line.