I'd imagine right up to 9.99.. startrek.com says they did 9.5 when running away from Q. So I'm saying 9.99 because at warp ten your everywhere at once and no physical object can really survive that. I know Paris did that but I think that was exception.
The fastest we've ever seen the D go was about Warp 9.7, I think when they were running from the Borg in Q-Who. 9.6 is the maximum rated speed and above that she starts shaking.Rayfire 16:51, July 17, 2011 (UTC)