The SLF400 is a car that was cut from Midnight Club II. It is only mentioned in the texture files, along with the Vampire, and does not appear in the finished game. It can only recovered by using mods such as MODern Edition or Midnight Club II: Decade Edition modification made by TEK Vito. It's based off from Pagani Zonda.
It's likely that Rockstar Games didn't have enough time to add this car to the final game.
- Theres a video which it shows SLF400 recovered by using a mod .
- This car could be a slower version or a predecessor of the SLF450x