One key difference between much Anime and Manga is that Anime based off a Manga(let's say...DBZ) will have things added to it, known as filler(as they fill up space, since comics can't be translated all that well as is unless they're EXTREMELY detailed). In DBZ's case, the filler even goes so far as to change strengths of characters. And then in the case of Trigun...Half way through, the Anime and Manga and exactly the same, for the most part. Then it's splits off, and they're COMPLETELY different.