B+W Slim Polarizer?

I don't think I need the slim since my widest angle is 18mm. But it seems to be cheaper than other b+w cpls, at least on ebay.

If I'm not going to be putting the lens cap on though, I'll want to be using a lens hood. Will my lens hood still fit with this b+w on?

Also the questions was specifically about buying from a Hong Kong vendor. Does anybody know if that's a problem? Gray market stuff? Fake b+w's??