When the MPAA were asked what would needed to be cut to obtain an R rating, they replied that if everything the MPAA objected to were to be removed, the movie would only be 10 minutes long.
Neuter Grandmother on Bus: I seen you, Sylvia Stickles, showing your pubic patch to the bus driver. You should move downtown where you belong, you whore!
What are the differences between the R-Rated Version and the Unrated Version?
A
Well, there are not less than 124 differences between both versions mostly due to little changes throughout the movie. Often alternate and much more cruder shots and of course more nudity can be found in the Unrated Version as well. All scenes cumulated the Unrated Version runs more than five minutes longer. A detailed comparison between both versions with pictures can be found here.
Q
Why don't the neuters just whack the addicts on the head to turn them normal? (And vice versa)
A
In order for a neuter to become an addict, or an addict to become a neuter, the concussion has to be an accident.
Sylvia mentioned this after Caprice hit her on the head to try to turn her back into an addict.