We had an old XY IR sensor from FMA but one of the sensors was smashed. However, there was still a good pair of sensors on the board that we could use for the Z axis. The club also picked up another XY module to actually handle those axes.
Smashed IR sensor
Additional XY sensor module
As with any RC hobby system, a pair of nice servo crimpers will be essential. Head over to Hansen Hobbies to pickup their very respectable deluxe crimper. Also be sure to spend some time reading through their article on servo connections.
Nice servo crimpers
Be sure to pick up all the related servo consumables