Ooooohh good conversation subject! Thank you!
Agree with Donnie Darko 100%
Michael Mann is notorious for editing his films whenever they are released on a new home video format. I have LOTM on BD but not seen it yet. Aware that there are two other cuts on DVD.
Dances with Wolves though, worth mentioning that the extended edition is not a directors cut. Kevin Costner stated that in the early 90's as that cut was prepared by the studio for it's TV premiere IIRC. Will fish out the article but he wasn't happy with it back then.
*edit* found it
http://thisorthatedition.com/dances-with-wolves-1990/