Version 1.0 includes the following:

The coffin from the Albany Lurcher (extra #1)
Interior props (navy revolver & hatchet) (extra #2)
New headlights
Teeth
Widebody kit
Livery template & dirtmap
Standard GTAV vehicle features (breakable & tintable glass)

Version 1.1 will include the following:

Tuning parts, exclusively interior ones.

Version 1.2 will include the following:

LODs (L0-L4)