heck if you are just doing springs the rears take 30min, and the fronts probably an hour. i had a mechanic i know do mine since i didn't want to mess with a spring compressor, but he only charged me $100 to do springs and ball joints.
not sure I'd want that bar in the back of my neck. even though it probably doesn't hit your neck, i'd be wear of having it there just incase of an accident, don't want to sever your spine. why not have it so it's on the back part of the head rest?