Piper is able to use her powers to vanquish vampires despite it previously being established that vampires are immune to witch's powers.
This episode was filmed with the intent of being a series, rather than a season, finale. To this end, the episode's title, "Something Wicca This Way Goes" is meant as a tip of the hat to the pilot, "Something Wicca This Way Comes."
An alternate ending was written for this episode. The ending included: Rose McGowan saying "I don't think we're going to get out of this one... alive", the girls are killed at the end, Leo never shows back up. But after reading this ending, writers couldn't agree so they decided to keep the original aired ending.
The last time new footage of the Halliwell manor is shown, stock footage was used in the final season due to budget cuts.