I am in the same stage as you are; I have a stock D16Z6 and am gathering info for a build. This is my 3rd D series engine (had the Y8 and a D15), while there are better platforms out there i.e. B, K, and H series, I like rooting for the underdog. The D will be cheaper to build, relatively, but you WILL have to spend some money in order for it to turn out right ... otherwise there is no point in dropping money into a D. I say stick with it as you already have a combo that people are currently hunting for (those folks trying to build a mini me or wanting to get their paws on a P28 ECU). It'll be fun man, check out
www.dseries.org for more info on tuning and stuff like that. I promise you won't have half the headaches of a Chrysler engine lol
(kidding, just had to throw that in there for kicks)
Let us know what you ultimately decide to do with your ride