building up an all-motor D-series would be expensive and not very fruitful... (I doubt you'd make more than 20 or 30hp in a streetable setup).

A stock d16z6 is a good candidate for turbo though... completely internally stock and well tuned, they can make upwards of 200whp (although something in the 150-170 range is more common).

Regardless of your goals, turbo is the right route with a sohc motor... now how much power you want to make determines whether or not its in your interest to build. IMO, building a d-series for turbo costs too much to justify... for what you spend, you might as well be working with a b-series.