I took out both the topmost guide and the one on the right side if facing the engine from the front of your car a while back. Neither is necessary, nissan has already confirmed this, you will be totally fine. My guides had a nice amount of wear, so it was pretty obvious that it is a source of noise for many people. While you're in there you can WD-40 your tensioner to get it moving again (dont let the chain chew up your hand like i did lol)
here is a link from the tech pages
http://www.nicoclub.com/articles.php?id=105618
dont forget to search there
edit - dont forget to torque to the right specs when you're done!