The SailMax.biz F18 (Dave Lennard and Mike Krantz) used Ullman sails (main,jib, and spin) on their Nacra F18 last year. They traveled a lot miles, and sailed at a number of different venues. I can't say they were faster than stock, but they sure weren't slower - go to www.naf18.com and check out the 2005 rankings...

As far as I know, pretty much the rest of the F18 crowd in North America is stock Hobie and Nacra sails. We saw a prototype set of North's about two years ago, but they never seemed to take off.

-Mike