Thriller: A Cruel Picture (aka They Call Her One Eye) was pretty controversial for the violence and hardcore porn scenes. Not a bad movie but not the greatest by any means. I own this one.
I think Caligula was another one I don't see mentioned that garnered a lot of guff. I didn't like the film personally but others think it's a classic.
Based on what you have I would suggest you get Thriller but make sure to get the uncut version because the other is hacked up horribly. Only controversial Swedish movie I think I've seen.
http://www.deepdiscountdvd.com/dvd.cfm?itemID=RYK030349
By the way, I've heard Mother's Day is pretty bad but haven't seen it. Been meaning to check it out. Freaks was pretty good too but it's old and some people just don't like older controversial films because they don't pack the same punch now as they did.