Their claim of "80% more power" puts it at 36-38 amps, depending on what they are comparing it to, which is a good improvement over the 21-amp Bugeye generator, but just above marginal for anything but a pure stock setup. If you don't spend most of your time idling with all the lights on, it should be OK.
I remember seeing a web site for a similar alternator, might have been the same, but I can't find it now to save my life. That site didn't mention weight reduction, just emphasized the original appearance. It also was breathtakingly expensive. Cool, though; I like the basic idea.