If you need an electric motor for a school science project you may select any kit. However, a good science project requires a lot of experiments. You may compare two or more of these motors. This comparison is valid and accurate as all the motors share the same mechanical design. If you plan to conduct experiments you may purchase one of the experimentation kits.
Every kit includes all parts necessary for complete motor assembly.
However, if you plan to experiment with these motors, you may want to order backup parts in case that any of them break. The parts that might be broken include the reed switch, hall effect switch, optointerrupter, and transistor.