Express International shipping to South Africa

Hello and thank you for reading and replying to my forum post. I must ask a few questions about how to send a package by express international shipping to South Africa. Since I will be shipping a package from my company's warehouse outside of Mexico City, Mexico, I suppose I should ask how this shipping will work between these two countries. Are there any preferred shipping methods to send packages across this great distance? Our customer has requested express shipping. However, for my own benefit, I will ask what are the differences between shipping by standard air cargo, and shipping by express air cargo? Will you inform us when our shipment has cleared South African customs? Do you offer updates sent to us by email that will keep us informed of each change in shipping status? I will also ask that if you have a general information package that you send out, that you please send that to my email address. Thank you for responding to my many questions.