the original looks like a piece of candy
I think A is my favorite for 'human military' looking technology. It looks business-like and imposing.
B is a very jules-vernes looking spacecraft, sort of 30s era sci-fi. have you seen the new look (um.. in the Last 4 or 5 years) at tommorland at disneyland (and i would presume disneyworld)? very retro and 30s looking.
C reminds me of something from that lame excuse for a tv show, earth: final conflict. not to say that i dont like C, but it has that energy-field sort of look to it, which is very cool. this would be good for a high tech, advanced race, not something from a grit-tech scenario.
I think that A and C look best as an entire composition, but I will leave the judgement to others. I hope my opinions on each look help you refine your decision. is not that I think the original is bad, its just that i think it looks like a piece of striped candy. if thats the look you are going for, then stick with the original. maybe the race portrait could be of a candy-striper
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"...the green, sticky spawn of the stars"
(with apologies to H.P.L.)