Hi Shane,
You do not need the PowerExpander to use the Equalizers BUT you will see improved servo performance on this size plane if you use a PowerExpander. Its really up to you, you will get more torque and faster servo response with a PowerExpander than just running off your receiver. If you are thinking about using 2.4GHz technology then a PowerExpander is a definite recommendation to prevent receiver reboots.
Please let me know if you have any other questions.