Hey, I'm actually DOING this very swap! You could re-use your HF tranny but I don't think you'd like it. If you can find a DX or Si tranny, get it and you can keep your axles (the spline count is the same 'tranny side' while the hub sides are in fact different between the HF and DX/Si)

Are you going to go OBD-1 like me?

We should keep in touch... to help each other out.

As far as wiring is concerned, it's going to depend on what all you want to do. Keep your OBD-0/non-OBD Injectors or upgrade to the OBD-1's? Convert your whole system to OBD-1 via a jumper harness? etc.... Let me know and I'll try to help ya out.