suigetsu would win w/ a better sword or a water source, choji beats him pretty handily.
spiked meatball tank keeps suigetsu on the defensive, even w/ kubikiri.
in base, baika no jutsu: choharite K.O's suigetsu
in bm mode, butterfly bombs kill him
Hard to say, Choji can't hit him as Suigetsu is pretty much well... water, and Suigetsu can't really harm Choji when he becomes as big as the Gedo Mazo, so it would probably be a battle of stamina, which I believe Suigetsu would win.