Sunfish,
You're right the DR is pretty darn close in design to the SS (we've made some improvements including more HP and others already discussed) -- but we took the "if it ain't broke don't fix it" approach. Paul, and his father before him, build an awesome machine and it's design has proven extremely durable. Why change that?
What we've set out to do is make these machines more broadly available, at a reasonable Price and backed-up by exceptional customer service.
Better you than the Chinese , nothing against China but ....
I hope it's a success !