Joe -
to give you the best answer I can - over here there are (so far!!) no speed restrictions, and we have 2 GPS readings
in my club (Jets of Norway) of speeds exceeding 260 mph - however, the guys in the Netherlands fly much faster.
Here is a link to a very slick delta that is said to do more than 320 mph, and still I think they could go faster, this video
is a few years old already!

Tor


http://www.youtube.com/watch?v=LYVBrMzg9mA

BTW: This very nice guy from Nigeria, Afrika offered me 10% of his entire fortune of 15.500.000 USD yesterday if I would just help him get the money out of Nigeria, He just needed all my bank details...