Randy does good for a one man shop out of his garage, I would have to say he has to be the most creative guys out there.
As far as stepping alternators up to higher amperage from a small alternator you always have to lose something, heat issues, less charge at low RPM. OE makes as small as they think they should to keep things reliable and with the charge being at the RPM's they want. If they could keep making them smaller, they would keep shrinking them until they look like a micro chip by now. You can step most alternators up 35-40% without losing a whole lot of low end power. I guess it depends on what you are using it for. For drag cars you can step them up a lot and keep it small, high RPM's and short run time, perfect.
I sell parts to starter and alternator rebuilders for a living. For the CS130D (normally 105 amp) I think I have a couple hundred 200 amp stators on the shelf to step them up. I talk customers out of buying them. They don't work worth a darn. Kids think they want a 200 amp alternator to run their stereos, fact is these put out way less power idling and driving around town then their OE alternator. They make power but the RPM's must be screaming. Larger alternators step up power much better