Be careful of DOA parts too...last time I visited, my sisters that live there tried to get me to build them a new computer within 3 days. So I did, only to run into some funky error while installing Windows. Never was able to figure it out before I left, and they had to get another guy to come in and look at it. Turns out the RAM was dead.
So unless you have a way to test parts right away, I wouldn't buy computer parts from HK and bring it back, period. And parts cost just as much if not more than U.S. prices for parts. I'd look more into cool electronic gadgets and gizmos while you're there if I were you. I feel like a kid in a candy store everytime I walk into those little electronic shops along the streets.