[1] = Good question, I would also like to know.
[2] = FPS Limiter, it is mainly used in competitive servers (race, dm). It limits the max FPS a player can have, the higher the FPS the more faster the person moves on land (and slower on water, afaik thats a bug). In races, people with 30 FPS would be slower than people with 70 FPS, even if they had the same car and the same timing. FPS Limiter limits the max fps