What did they cut to get an NC-17?

Yes it was. The MPAA isn't the only authority on what gets rated in America. Just because they didn't give it a rating, doesn't mean no one else did. Central Park Media gave it's Rating Anime 18, which inspired the adult anime company Anime 18's name. And Anime 18 helped to create Urotsukidoji part 3 and 4. Furthermore, if you look at certain websites, they will make their own rating for it. They are usually very accurate. No one is going to be crazy(or foolish) enough to label Urotsukidoji a family film rating of G. The bottom line is that depending on how much editing was done, the rating system changes to meet those accomodations. Certain countries even have different standards than in the U.S. But one thing will always remain the same. Overfiend, whether it's cut or uncut, is a strictly adult film.

I haven't seen the movie recently so my memory of how long it is is fuzzy at best. As for the Perfect Collection being hardcore, yes, it is hardcore. It has some hazy looking blur to it but it isn't that effective. You still know what's going on and the shadowing doesn't exactly shade well either. The silhouette can still be seen and you know exactly what's happening. In every sense of the word, no matter what the "normal standard" of porn is, it is definitely a porno flick.

I dont know about the perfect collection version but the running times of the uncut versions are
150 mins for this one
and 100 min for part2:demon womb