So, I will be going back to Asia, and my uncle want to buy me an Alienware laptop or ASUS ROG laptop. But I'm worry that, if I bring it back to North America and it has problems and North America might not cover it, because i bought it in Asia. So does the warranty cover internationally or just where you bought it from?
Dude No.... That's not the case. You can only upgrade the HDD/SSD or RAM on an ASUS ROG laptop. I'm assuming you're talking about the G750 model.
It has both CPU and GPU soldered to it. It's not customizable. Get a Sager or MSI if you want to upgrade it sometime down the line.