Here's the link for Internal Affairs if you've never seen it, the subtitles are hard to read at times though:
It's the first Asian film I've ever seen (unless "Better Luck tomorrow" counts) and I was impressed how well it was done, but I wish they would of made the film a bit longer. I don't think the Asian flick explained some things as clearly as they did. For example they should of spent a few more minutes on the beginning to explain the training, to explain on how Matt Damon's Character got up through promotions and why he had a special bond with the boss, and I wish they would of shown a bit more on the boss himself.
All in all, good film, but I don't think the American Version was much more polished and had a better storyline. The actors in "The Departed" was the best I've can remember in a while, and other then DiCaprio's character in "Internal Affairs", they were alright, maybe it's a cultural thing.