As previously mentioned, K-1 has announced the first 13 of 16 Grand Prix participants, with the last 3 to be determined by fan voting. That voting is now up and can be done here. The only catch? The voting page is only in Japanese.
Thank to Babel Fish, the fighters listed on the page are, in order:
Hong Man Choi
Chalid Die Faust Arrab
Mirko Cro Cop
Vote now and enjoy the Final 16 on September 26.