Tuning your e-bike does not mean making the motor stronger.

The power remains at 250 watts, but you get motor support beyond the 25 km/h limit. If the 250 W support normally stops abruptly at 25 km/h, the pedalling power required to maintain the speed is not pleasant for many and is perceived as "riding into a wall".

This can be prevented by tuning. The motor support is there for longer and only when the combined motor and human power can no longer stand up to physics (air and rolling resistance, slope downforce, etc.) is further propulsion slowed down slowly and homogeneously.