You don't need DS to use V4 or M4 textures on K4.

The K4/V4 mixer script also works with the Gen 3 figures (Luke/Laura/David/Stephanie/Victoria/Michael). Can't mix between Gen 3 & Gen 4, but there is software to move Gen 4 textures to other figures.

At the end of the day, Poser gives users the ability to decouple content from the figure it was designed for originally, which is why I stick with Poser (not to mention that it is a much, much better written piece of software).