Rep score is a whole different story. I don't think powering down will effect your rep score, but don't quote me on that.
If you decide to power down you entire account, after 13 weeks your STEEM power will be at 0, assuming you do not earn any more STEEM during the power down period. When you power up, STEEM is instantly converted into SP.
So does having a higher steem power make my ranking go up more or faster? Also does having more SP make my content rank higher and show above others with lower Steem Power?
Having more SP will increase your voting power. The fastest way to get your rep score higher is to interact with users with higher rep scores than you. If the higher rep score users upvote your content, your score will rise.
Having more SP will not outrank your content over someone with less SP. With more SP, you could however upvote your own content, which would then rank higher than a fresh new post with no upvotes.
I would recommend that you use steemworld.org/@YOURUSERNAME to track your actions and how it affects your rep score.
Thanks I appreciate the info. I'm still learning how the site works.