Well if it is a feather you are looking into. There are two main options in my eyes.
Argos 12v drill motors (money saving)
Gimson motors (twice as expensive but very good, this is what i am using)
For speed controllers
Scorpion XL or XXL
electronizes
Sabertooth
They are all similar prices but scorpions are a bit more expensive and they are the esc i am using
12v battery i am using nimh
For radio gear
Planet 5
Spektrum dx5e or dx6i ( i am using dx5e)

This the basis of a robot PM me for links if this is what your looking for.