I doubt this qualifies as Manga, but I read the Kick-Ass series. I'm not a comic/manga reader, except on rare occasions, and I swear the movie is on Dish every other night (and i've seen it way too many times to count), so I thought it was time to check out the differences.
All in all, pretty faithful adaptation of the comics. There are a couple of pretty big changes, but for the most part it stays pretty true to its source.