[240racer]

I don't think you will be able to use a DSM dp since the turbo on that car is between the engine and the radiator, and rotated 90degrees. I think you will be best off with a custom DP, should be able to get something made for you at a local shop. What manifold are you running? I think that's maybe more important, if you are running the revhard one like everybody else, then probably just go with a straight T3 (not sure what trim, etc.) it would be good for our engine with 6lbs. The t25 is going to be a little small for you, our engine has more displacement and at 6lbs of boost with stock compression ratio you will be using more air then the sr20 did stock. Also remember that oem turbos are on the small side for whatever application, because common idiots (the kind that like the feel of mustangs) don't like the feel of a properly sized turbo (for performance driving) The 2g DSM comes with a t25 as well, but it's a 2.0 liter with 200hp, which is about the same as the sr20.
If you don't plan on boosting over 12psi, then I think you will be fine with the T3. I wouldn't worry so much about ordering a DP that fits, because I think it would be too hard, unless you just get a kit (which is maybe what you should do since you don't want to weld a custom one)