Was looking around for a video of a KMS dojo run and found this.
http://v.youku.com/v_show/id_XMzQ3MDU0NTI4.html
It seems like KMS has nearly no spawn lag and minimal portal lag compared to GMS.
I believe that an extra 1-2 minutes would be added to the time if this run was in GMS, which makes those GMS 8 min runs even more insane.