This post is from the series of YouTube videos by richpin who mainly works on a Saturn Series S with a 4 cyl DOHC engine. He found this tool at Auto Zone for only $12.99 and bought it. he says this is a bargain compared to the price Snap On was asking. This is a 15.5" 3/8" drive extension with a 5/8' spark plug socket on one end. The great thing is the socket has a swivel and the socket also has a magnetic insert to hold the plug as you remove it. Be sure to look at his other videos in the series.
http://www.youtube.com/watch?v=fuYkB7Poi3Q&feature=channel_page
http://www.youtube.com/watch?v=fuYkB7Poi3Q&feature=channel_page