With the recent nerfs, how do I get the updated cards? Do I even need them?

There are no updated cards. You have to remember them from the FAQ.

If you're using sleeves, you can slip a note in with the card or put a sticker on the front or something, but mostly you just want to have a current FAQ available to reference at tournaments.

When their sources are next reprinted they should contain the cards as they exist then. That's to say that when they reprint the Raider you'll get the update Palpatine if you buy one of those.

11 hours ago, digitalbusker said:

If you're using sleeves, you can slip a note in with the card or put a sticker on the front or something, but mostly you just want to have a current FAQ available to reference at tournaments.

Personally, I recreate the card using Strange Eons and slide the new update in the sleeve over the original. Works for me, and nobody has complained yet.

You can also copy and print the image on the article presenting the FAQ -> https://www.fantasyflightgames.com/en/news/2017/3/6/bringing-balance-to-the-force/

Or for the lazy guys :

Manaroo https://images-cdn.fantasyflightgames.com/filer_public/97/ff/97ff270a-e591-410c-ad66-c447c74f4ee9/manaroo_new_web.png
Palp https://images-cdn.fantasyflightgames.com/filer_public/4b/e0/4be04c3a-fbcd-4534-8540-1a0af64ef927/emperor_palpatine_new_web.png
Tie X7 https://images-cdn.fantasyflightgames.com/filer_public/a5/ce/a5ce1973-22a8-46ed-a75d-60fd775716da/tiex7_new_web.png
Zuckuss https://images-cdn.fantasyflightgames.com/filer_public/34/c8/34c8c243-0ad4-45aa-9023-a03dc19ff0bf/zuckuss_new_web.png

I have several unoficial alt art cards. I like to use them because they are just cool and/or funny.

I have official alt art cards (BB-8, Darth Vader crew) whose text is in auberesh (unreadable to most without a translation sheet).

In both these instances, I slip the alt art card into the sleeve, on top of the original.

Nothing to stop you printing out the new copy from one of the articles and doing the same thing. You don't even need a sleeve, just always have the original official card to hand.