Thanks Dream!
😄@r4v3n: Your best bet is a reseller. They will offer a degree of support on top of the support you get from Asus (though Asus is the one to generally provide service). Popular online retailers like Amazon and Newegg tend to have good pricing, but you lose out on customization and that additional layer of technical advice. Also, I don't think said online retailers conduct any of their own benching/testing prior to shipping the product.
And having a reseller perform upgrades does not void your warranty as long as the reseller is verified by Asus. Doing it yourself risks it, but only if the upgrade requires exposing the main board/opening up the case.
We customize Asus, MSI, and Clevo laptops!