Ok we all know that franky gains a different hair style and powerup/powerdown(is that even a word) when he inserts drinks into his stomach, with his basic one being Cola. I think this is definatelly foreshadowing for Franky's future capabilities, so let's speculate
Franky+Energy drink/Gatorade= Stamina Franky with a harder body and durability and Pompadour hair style (like rio from Shaman king)
Franky+Coffe= Hyper/Speed Franky with a Spiky hair style
Franky+Zoro's sake=Unpredictibility/evasion/countering Franky, with Crocodilelike hair (pulled back)
That all I can think of for now
Also Molekage from Narutofanforums mentioned that they didn't have to be drinks and said that hot sauce to boost his fire capabilities and makes his hair move like fire, which I found very interesting:happy: