Chuck H,
I'm really happy with my engine and find it to be quite streetable. It is not for the faint of heart, however. It has a rumbly idle and sounds like it wants to tear someone's head off. It is perfect for what I wanted -- something rude, crude and flagrantly anti-social.
I'm pleased to report that the cooling issues are all fine -- water and
oil temps all stay on the lower end of the scale.
I'd go for the potent version, but what do I know?
BTW, I'm using a David Kee Toploader, and I like it. I five speed would be nice, but availability and durability in this power range is a real question.