If it comes out after the Access Hollywood tape OR news of Comey re-opening the Clinton investigation then I think it definitely swings. Trump was floundering post-Access tape and what got the narrative changed was Comey re-opening the Clinton investigation, which pushed the Access tape to the margins again and gave Trump's last few weeks some breathing space.
If the Daniels issue comes up, I definitely think it depresses some of the social conservative vote for Trump just enough. After all, we're talking about less than 100k votes across three states here to give Clinton a win.
If Comey had kept his mouth shut Clinton would have won.