You can bash me for my rating, but it was 986 two years ago, so I am improving. I'd rather put in the work and learn the Najdorf.
Nothing against the Najdorf (it is my preferred defense as black), but I would suggest that you might see faster improvement by spending less time worrying about openings and more time working on other aspects of the game (specifically, tactics, opening principles, and endgames).
Sadly...it seems that many low rated players would rather sound like they know what they are doing, than actually know what they are doing.
I'm goofing off at work. The book is on the second shelf in my living room with all my other chess books. ...
^^^^^^^^^^^^^^^^^^^^