Have you thought of the ATLAS 4.2 out of the trailblazer? Westers garage can re-flash the ECM and get you a bit more power besides turning it into a 5-wire installation (Ignition, Crank, Bat, Ground, fuel). Other than that, swapping a late model driveline is easy - get the complete donor vehicle and transfer everything. The gauge wires can be separated from the rest of the harness to slim it up a bit, or you can use the wires to feed the gauges.
Steve and the guys at Street and Performance re-programmed my Camaro 3.4 that I had in my RX7 about 10 years ago. Remember to purchase the VATS bypass as well unless you keep the VATS intact.
An odd but great combination would be the Caddy Northstar and a built up 4l60e from a 3.1 S-10 or 3.4 Camaro. Keep the Northstar from a 94-95 for OBD1 and there are a lot less wires and sensors
