I've had the same dream as you for awhile. It's not really a goal at the moment, but more of a "maybe in 10 years" thing.
Since these aren't very common I have a hard time finding weight info, but the one source I've found(coincidentally, the last thread you linked) says 222KG. That's hardly more than an L28. When you make the block out of aluminum you tend to save quite a bit of weight. Swap out the enormous intake manifold for ITBs and it might be a wash from the stock balance.