If all you want removed is the “Noooo”, then you should probably track down the 2004 DVD version. Vader’s line was added to the movie for the 2011 Blu-ray release. There are some other changes in that version too, but none of them are as noticeable as Vader’s “Noooo”.
While this is true, I’d rather go with the 1997 Special Edition if the SE is what you want.