363111 right lower rear arm kit (composite) is the same number used for the '15 arm.
363121 left lower rear arm kit (composite) is the same number used for the '15 arm.
The front arm part number has changed from the '15 to '16 car and so has the shape. The rear arm part number has not.
That pretty much what the PN numbers I listed for the 16 suggest in a nutshell.