Diplomatic permits aren't required for China, however having a local sponsor is. The process has been made a little easier over the past couple of years, however the quality if your local sponsor will make all the difference in the world. ATC won't be an issue for you in a Kingair, however be prepared to spend a lot of money on ground handling and agent fees.
If you plan on using Universal, you can plan on spending a lot of money with them too!
amraam