Check out "Gas Bike Alley" group on Facebook. Jack Allison recently ordered one of these kits and is documenting assembly and testing in this group.
So far, it looks very interesting! I have seen video of a rider from MZMiami, but it was very slow. Claims of better speed&power have not been documented yet.....but LOTS of folks watching carefully!
The vid I saw sounded like the engine was blubbery rich and not running anywhere near right, so I'm not yet ready to ignore this.
Claims of 5hp seem a bit much, but rumors has it they rip with a pipe. Waiting for more info myself.