R2 Remote Speed Modes

Just kinda confused about the different speed modes on my GTR/R2 Remote.

Do the different modes (Ecco, Cust, Pro, GTR) only adjust the acceleration or top speed as well, or a combination of both? Can somebody explain simply how they all differ and basically what each does?? I've watched videos and read the manual. Sorry for the rookie question! Thanks guys!

 

The different modes do not affect top speed only the amount of power that is drawn from the battery so each mode gives higher immediate power and more hill climb and acceleration