1. First let me preface by saying what I and many others have said here for years - and that s that at its core, Google is a search engine company and their goal (other than to make piles of cash) is to provide the best search results they can. Because once their search results become inaccurate (you search for hats and get shoes), then users will find another search engine.
2. I'll also reiterate what I've also said that as long as you are using white-hat (legal) techniques and genuinely trying to honestly improve your website then you should not have any problems.
SEO can be broken down generally into two parts: on-site SEO and off-site SEO. On-site SEO is what you do on your website (content, etc), whereas off-site SEO refers to things that are not on your site (e.g. who links TO you, among other things).
That being said, it's always a great idea to get as many INCOMING links TO your site as possible, but higher-quality more relevant links are better
Nobody knows for sure what the exact update will be or when the update will be, but I've read that the update will make it that much more important to have more relevant links to your site, as opposed to having a ton of not-so-relevant links to your site.
If your website has a ton of links from websites that are not very relevant (example below) or are paid links or simply spammy links to your website, then you may see a decrease in your search engine rankings. This is not a penalty per se, but it is alleged to be a shift in the algorithm.
I'll explain this "relevant link" stuff with an example:
Let's assume we have dental websites A and B that are both about dentistry and both have quality, original content.
Websites E. F. and G are websites about dentistry and they all link to website A.
Websites X.Y. and Z are about sports cars and they all link to website B.
The idea here is that when a user searches for "dentistry"..... (note that "dentistry" is a ridiculously broad topic and isn't a realistic example, so don't be 'that guy' and reply to me that "dentistry" is too broad a keyword -- I' trying to demonstrate a concept)....given the choice of websites A and B, website A will probably rank higher in search engine listings because it has more sites that link to it about dentistry -- which is the subject of the user's search.
Interesting Side Note
This is Penguin 2.0 or Penguin 4 depending upon who you ask - so the last Penguin 2.0 wasn't really 2.0...or so they say.