Yep, I know that shop as well. It's called A-Grade iirc, not only do they sell the e3's but they also stock daps and memory cards etc. I find that they offer the cheapest prices in both 黃金 (Golden Arcade [the one on G and B1 floors]) and 高登 (Golden Computer Arcade [the one on the 1st floor]).
Edit: I bought my E3 from music souffles. Pretty good service, let me test it beforehand to see if it was working or not.