CDJ400 - Chinese Voltage and Grounding Issues?

Right now I'm visiting friends and family in the US before I go back to work in China. I just bought a pair of CDJ400s and a bunch of other dj equipment to take back with me. It's a million times cheaper than buying it in or mailing it to China, where luxury taxes are high on imported electronics. I know that everything is made in China, but everything nice leaves and has to be imported back in.

Anyways, my first question is: Even thought they say the voltage is between 100-240V, is that actually the case? I have had many laptops listed as 100-240V capable implode/explode/melt/commit suicide on me in my many years in Asia. So do I need to use any kind of power adaptor or converter with them?

Second question: Not many building have grounded electricity in Asia, especially China. Laptops always buzz with a current that you can feel, metal parts will shock you. Iis there a chance of electrocuting myself when they're plugged into electrical sources that aren't grounded?

I have a Xone:92 as well, so same questions for it if anybody knows.

Thanks,
Sam