Only place that is good in HK for being a dealer is in Supreme Co.
I was in HK last month and visited Supreme Co. It is located in Mongkok, HK. The MTR station you want to get off at and look for the Park-In commercial center (56 Dundas St) is Yau Mai Tei Station, exit A2.
http://www.supremeco.com.hk/walkinstore.html
Looking around their website, the prices seem reasonable. Their selection is also VERY large for an overseas place anyway.
I did see a place (near Supreme Co. along the airsoft strip) with a Surefire M6 (kind of old looking) for roughly ~$3200 HK dollars. In USD that is ~$410. Not that much over $392.00 MSP. In HK you can also haggle to lower the price some.
http://www.supremeco.com.hk/catalog/index.php?cPath=1_26
Some stuff seems to be on sale (like the A2 in BK, and KL3 in 1W form.)
Also be on the alert for fake knock offs as Trashman said, but usually you can spot Surefire's by well their build quality, it actually says Surefire, and look for packaging (like serial #'s, warranty cards back to the US and such.)
I imagine the U2 to be MSRP at $270 US but you can try to lower the price, because its HK, you can haggle! LOL.
Have fun while your in HK and be careful to keep a limit or you'll be back in Singapore with too many Surefire's! (haha, you can never have enough SF lights, budget allowing though, they can get expensive.)