Just over 42 mph on the Torq, down a steep hill on which even my Twist managed a slightly terrifying 38.4 mph once. By contrast, the Torq was completely stable, and I think it's high speed handling compares favourably with a motorbike's. Not on corners with those Kenda tyres though.
That was the limit though, wind resistance preventing anything more, so I'd need to find a hill much steeper to exceed that. Since the Torq wouldn't be able to get back up such a hill, I'm in no rush to do that!