A turbo is tought to tune, thats probably why the SC guy had trouble. Also, I'd have to see his setup. What turbo was he running? How much boos? What waste gat? BOV? did he use the piddly SC FMIC?
I too have contemplated this, and I beleive I have a recipe. Big single, Grand National style. I have compiled a good bit of parts to turbo my Modular 96, but money is running tight, I want a different trim, and I cant have the car down for that long. BUT! I want to see a fast turbo bird, done right, so hit me up on PM if you want the gear. I have a T04E .60/.81 (good for 450bhp), a 20"/15" FMIC, and a Gredy Type S. What you will need is bigger injectors (42#+), a fuel pum (255ish), Some way to tune AFR dynamicly (AFC, SAFC etc..), and an external waste gate, I recomenend a Tial 40mm. The 3.8 will be MUCH easier to plumb. You can get a set of headers from a 96-97, they are tubular, then use those to hack and weld yourself a couple foward facing manifolds.
There is a guy in Eastern ohio with a flood damaged 93 3.8, he's selling the engine, recent rebuild, Supersix Performance stage 3 top end.
If you have any more questions, feel free to ask. I'll love you help you out on this! Dont pay attention to the nay sayers that claim its a rice mod, or its not worth the trouble. Keep in mind, some of the fastest mustangs on the planet are running turbos. And you seem to be doing for the same reason as I, to be different