Due to the design of the E175 scooter, there are no bolt-and-go or plug-and-play parts that will make it go faster. Increasing its speed requires custom modifications which may include modifying the frame and custom wiring. If you are up for modifying it then please let us know what your top speed goal is and we can make modification parts recommendations.
For use on flat ground with some gently sloping hills, a 350 Watt motor could be safely geared for a 16 MPH top speed or a 500 Watt motor for a 19 MPH top speed. The smallest SLA battery pack size we recommend for a 350 Watt motor is 8Ah and for a 500 Watt motor is 10Ah. The dimensions of these parts are listed on our parts site so you can play around with fitting them on the scooter or modifying the scooter to accept them.
We have a Top Speed and Gear Ratio Calculator which can be used to work out the drivetrain parts needed for a certain top speed.