Um, this ISN'T a film about Gram Parsons, and doesn't pretend to be. It seems to me that people who like the music of Gram Parsons wanted to see a biopic, and they don't like the fact that this is a comedy about what happened to Gram's body.
In fact, I'm not sure if some of the reviewers have actually seem the film. FYI, the guy with the beard is Phil Kaufman - Gram (seen in a dream sequence) actually doesn't have a beard in 'Grand Theft Parsons'.
If you're a 'Grampire', I suggest you give this movie a miss. If you like great fun road movies, pick up a copy and make your own mind up.