I was in Hong Kong, Macau and Southern China a few months back, saw a few E34's while I was there, none of them were really nice or looked after though, and most were 520i's or 525i's. They certainly stand out though in amongst the endless sea of no-name cars
Not much happens in Macau, there's not much to see there really, except for the casinos if you are into that.
Hong Kong is a lot more interesting, lot's more to see. Very busy, and very expensive though.
If you get a chance, pop over the Shenzen on a 1 day visa, it's a nice place.
Have fun!
John