JSA(joint security area),friend(direct translation might be freind, but the content is friends)and shiri had big impact on korean movie business recently. 
I really liked JSA and Friend. 
For someone who is not a korean, I strongly recommend JSA. 
Translation shouldn't be a problem. As long as you pay attention to the film, you can really enjoy this film.
I think freind is a film that international fans will have a hard time to really appreciate the film. Because there are a lot of local tastes in it. Translation might be a big problem. They use a dialect from a certain city. I am from that city so I can really enjoy the uniqueness of the film.
However, if you get a chance to see this movie, don't miss it. It's very entertaining movie. It reminded me of Goodfellas.
Some extreme violences are portrayed in the film