I just installed the Western Digital PiDrive on my Raspberry Pi 2 using a regular USB 3.0 to SATA cable that was laying around. I didn’t use the WD PiDrive Cable Kit - which comes with PiDrive cable, 5V 2A power adapter and USB 2.0 cable - as apparently it works as long as you have a capable 5V 2A power supply.
Also, I’ve added the following line to the config.txt - following the instructions in the card that came with the drive.
More interesting and useful information in this post https://community.wd.com/t/welcome/134719/7
First published on April 11, 2016