You get a superpower, but the user below you gets to pick side effects.

[Risviltsov]

You can be fast, but in any collision where a part of your body succumbs to >2 G force, you die, instantly. This also means that you cannot accelerate or retard faster than 19.62 m/s/s. You said nothing about acceleration/retardation and I assumed you spoke of top speed.

I want to be invulnerable to everything.