You can add your own parts and equipment etc in the unity version. The unity version works with the free unity download. I would suggest using that as it has more available to you that allows you to add things to it. The truth is, this was built in unity for unity. At first, I wanted to use the stand alone version as well but since it's built in unity for unity there's more power and incentive to use the unity version.
P.S. I'm with you on the Chibi Chars... *BARF* LOL