Yeah, the turbos are cool. And something I have seriously considered.
Here's my issues with them (this is with regard to the fact that I REALLY want an engine cover):
1) I would have to have custom water injected manifolds built....or use CMI headers at a cost of $3200 not including the tailpipes.
2) Lots of plumbing. LOTS. Heat exchanger for cooling the turbos, and potentially a second heat exchanger for the intercooler.
Overall, I think the cost of the complete turbo "kit" would easily be $8500 or better....compared to about $5500 for the Procharger. With a max hp goal of 700, the D1SC Procharger can handle that easily. The turbos would, of course, make it easier to make higher horsepower in the future with more cubic inches. (Yes, the 383 can make more than 700 hp...but I don't think it could do it reliably at sustained high rpm)