Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.
What are you wanting to upgrade from/to?

Any internal hard drive changes will void the warranty, ram shouldn’t matter just keep the standard ram supplied in case it needs to be sent in to Apple.
 
Not that hard to upgrade CPU/HDD's, but will void warranty - If it's done super cleanly, they'll never know it has been done though.

Upgrading RAM will not void warranty.
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.