1st beat the partsun ralley.

2nd fly using wings of wind to ninja park, and there'll be a house with an old man in it. Go in and beat him. You'll get medaparts for eggy. after that fly to medoropolis and fight koji at his house. get all the parts for warbandit. Equip warbandit with the "!" medal.

Your party should look like this

leader: Eggy prtnr.1:Warbandit
medal: alien !
head: omelette tension up
arm:hamlette shoot barrel
arm:ham-egg range shooter
legs: half-egg abductor

prtnr.2:Cherub (partsun rally prize)
medal: angel
head:cherub body
arm:cherum hand
arm:cherub arm
legs:cherub leg

This party helped me win all my battles.