Hi tonschk,
Thanks for your message and that good question.
The green version contains some changes in the frame of the Kaze JYU Fan. We tried to improve the compatibility for mounting the fans. The purple packaged version had the fan mounting holes on each side connected by "Ribs" but the green version has them open, as you can see in the below image. This is the change, nothing more =)
Cheers,
Shinigami