There are 2 versions of Vex 4, v1 and v2. v1 makes it so you can jump further and I believe your running speed is slower. v2 makes the jumps a bit higher, but less far, which is why Act 3 is impossible on v2. I also believe that you cannot do the Act 1 clip glitch in v2, and v2 is on most websites. The Act 1 Glitchless WR can only be broken on v2, as you need to accelerate a bit more. In my opinion, v1 is a bit easier to play when not speedrunning glitchless, but v2 is better for glitchless (unless you are doing any%, in which Act 3 is impossible and you are forced to use v1). If there's anything I need to modify here, let me know.