to remove the arm, just pop the end up, remove the nut and pry it off (put something between what you use to pry and the paint)
to remove the motor, open the trunk and pop out the two plastic button looking things on the bottom, then grab the handles and just pull straight down until the panel comes off (you may have to remove a couple of clips from the trunk and put them back in the panel) after that's done, just remove the washer hose, electrical plug and the three bolts and it comes right out
you'll need a 1" rubber or plastic plug button to fill the hole, if there's a Fastenal store near you they'll have them, but make sure you have the plug before you remove the motor because they may not stock them
good luck, this one cheap, little mod makes a big difference in how clean your back end looks