Spy Report: Grievous' injuries ties in Vader's suit
This was on MF.com
The Tie that BindsBy now, most hardcore Star Wars fans know about the droid general Grievious. He is one bad motha trucka, mowing down Jedi in the cartoons, smashing up Obi-Wan in the opening battle, but who is General Grievous? Well, he's not Darth Maul... he's not Sifo-Dias... he's General Grievous!
Yes, unfortuantely his background prior to being machine-bound is not revealed to us, but he is essential to the plot. Although he dies fairly early in the film, Grievous has an impact that reaches far into even the Original Movies: Darth Vader!
Now, I know that it has been confirmed that Grevious is not meant to look like Vader. I heard George himself say this. however, the technology behind the cyborg does tie it all in... sort of.
You see, during the course of the film, Grievous is badly damaged by none other than Ewan MacGregor! After this, Grievous flees to the neutral, medical planet Utapau. Obi-wan follows him there and eventually kills him, but not after it is set up that this is indeed where he was 'born'. (Basically, he was saved by a radical procedure perfected there in which a barely living or sometimes recently dead being is revived when need be and melded with the mechanical to remain alive.)
Anyway, after getting directions to the place where Grievous is repairing himself from a member of Utapau's upper caste, Obi-wan follows him there where a fairly anti-climactic fight takes place and Obi-Wan shoots him.
Later on in the movie, this is where the Anakin Skywalker we know and love/hate becomes Darth Vader, in a room/cave very similar to where we see the general earlier on. This also establishes Darth Vader's dependence on his suit. It is established that it is a radical, life saving, procedure for those who would have otherwise died. not a way I'd want to live, but hey...