R rated vs. Unrated Texas Chainsaw Massacre 2. Difference?

[cinema sickness]

In 2000 MGM release TCM2 in a bare bones DVD release with an "R" rating. Then in 2006 MGM re-released TCM2 in a "Gruesome Edition" DVD with an "U" rating. I've looked all over the net to see if the 2006 re-release was actually a different cut than the 2000 release but I cannot find any information. The run time on both are only different by 1 minute (100m "R" / 101m "U"). The only real info I've gathered to perhaps think there is no difference is that originally the film was released as "Unrated" but later given an "R" rating for home releases. Also apparently there is an uncut version of the film and this is not it. Anyone have any information on this? Thanks!