Regarding "Serbian Film": I've been following discussions on German boards regarding this one and it certainly appears to be the next "big taboo breaker" (though with a little more thought behind the "shocking bits" than the likes of AU and MSP).
As it's said to contain- apart from the "usual" graphic sexual violence- very disturbing scenes with a baby, I'll most likely pass
...There's enough other "extreme horror" titles left to catch up with.