It's hard to tell exactly which teams will be competing, and who's on which team. This will definitely be an interesting GST since a lot of the best GSers are now with different crews than usual, or not competing at all. I've really only seen a few teams practice consistently so these predictions will be based solely off those.
Mixed top 3 (in no particular order):
Whitebeard
TEAM BEER
Immortal
iDev top 3:
Amity
Trollin
RD