Yeah that original list is how i started watching sick movies years ago. After seeing all of those ,I dont agree with their order, but whatever.
Only ones I would add to the list
Slaughtered Vomit Dolls - Its a really really shitty movie, but it is sorta gross, could have been much worse though. Think a really bad Murder Set Pieces meets Mordum.
Feed - This movie is just messed up, like nothing makes me uncomfortable, but i didnt want to eat after watching this one.
Salo - two words, eating poop. And even though its not real poop, it sure convincing.
Visitor Q - Sick dosent have to mean violent. In my eyes sick is pretty much this movie. Picture the wierdest hentai you could think of, now make it into a movie. Incest, necrophilia, lactating, analshit sex.... yeah, its damn hilarious though.
The guinea pig series is messed up, but most of them are rather weak comapred to the previously mentioned flowers of flesh and blood and Mermaid in a Manhole. Not as gory as FoFaB, but pretty nasty nontheless.