Ooooh boy. I searched the three pages on the versus and hadn't seen one of these.
I don't even know who I think would win.
Minato, rasengan creator, hailed as the fastest shinobi of his time and a better FTG user than Tobirama, its creator.
Tobirama, FTG creator, Suiton master, hailed as the fastest shinobi of his time and able to compete with Madara in life (admitted by Madara himself).
If they both believed the other was a threat to Konoha, who'd be standing in the end?
EDIT: Both are at their prime in life