With ECU stuff OBD1 really is the way to go, because whether or not you decide to chip it or put an S300 in it, it's basically the best choice to use an old OBD1 ECU.
I've actually got a S300 installed in my Civic right now and since it's a pre-facelift it already was OBD1 from the factory.
But OBD1 conversions are relatively easy and well documented online.
Depending on your personal tastes you could also go with a standalone ECU like a Link or Haltech unit.
They cost roughly the same as a S300, but offer a very different featureset and more modern management options. (But they are not plug-and-play)
And while I don't have any experience turboing cars, I'd say a relatively safe power figure for a D16 would be 160 to 180-ish hp. (Those conrods are thin)
Already took apart a spare D16Z6 that I bought this summer, as I plan to completely rebuild it for a high comp NA build, and when I held those tiny little spaghetti-conrods in my hands I almost couldn't believe that those suckers manage to survive regularly hitting 7500RPM!