you can perhaps upgrade it with a lot of modding, but at the end of the day you'll have two MAJOR limitations staring at you:
1. battery life
2. heat dissipation
while the first can be somewhat ignored, the 2nd can't. the Dell xps 15z isn't build to handle the type of heat the parts you mention will dish out, and your computer will end up down throttling.
so all in all, while I don't think upgrades that far is possible, even if you somehow do it, it still won't give you worthwhile performance
any suggestions for a better fit?
the battery life isnt my biggest worry travel still has outlets
heat is very understandable. it is why im asking before trying the modifing first