2. Personally, I think it is more effective to attend some exhibitions. I don't have a booth, just go in, talk to foreigners when I meet them, and collect their business cards.
To tell the truth, it is generally illegal to provide customs data for sale, and it is not recognized by law. They all do it in secret. My friend's company has bought such information before, and the general information is ok and true. I recommend a company whose website is/index.htm.