The reason Bowser is used is explained in the guide.

https://www.speedrun.com/Van10/guides/g642c

I don't know much about in-game speed, sorry. Also I'll explain why Bowser is used in most events.

• High power (power affects acceleration).
• High speed figures.
• Sufficiently high stamina (don't know how stamina affects acceleration).
• Large hitbox (both advantages and disadvantages). Status meshes with game specs. This is why Bowser is used. Bowser dominates this game. By the way, Bowser and Vector have the same stats except for technique, but strangely enough, when Vector competes in luge, he is 2km slower (probably because Bowser's technique is 1 higher?).

Thank you.

I thought my account was hacked lol