Well, I'm probably the wrong person to ask because I'll dive into anything, sometimes with reckless abandon, and fix stuff "for fun"

That being said, if you have a little fine dexterity, are the kind of person who can take their time, are willing to cross check online if there's _any_ question about something (ex: "How does this connector release?"), then I think you'd be OK.
I guess what you have to consider the cost vs. concern, i.e., what if you do wreck something? Snap something off the main PCB even if that's very unlikely, and you're probably looking at a $500-700 repair bill vs. just paying the $600 for 32GB RAM up front, no worries.
The other factor: if this really does "void the warranty" (though I still think the jury it out on exactly what that means ...), you don't get that peace of mind for a year that there's no extra costs (or for __three__ years with AC+ for only $99).
I'll be honest: the warranty thing really bothers me, I like having my main work machine covered, there's an Apple store < 30 minutes away so it's convenient, I like that peace of mind, If I save about $300 only to have the main logic board fail, or the PCI storage crap out, and then have to OOP that repair cost, the savings are pretty much offset (if not upside down).