You will.
- GTE has 2 knock sensors, GE's have only 1 knock sensor.
- The Air Flow Meter design is totally different, so is the wiring.
- Ignition is no longer done via a distributor, it is on a coil pack system, the N/A Harness won't plug into the coil pack.
- The N/A doesn't have a cam position sensor like the GTE does.
- Various other things.
At the same time, keep in mind, that you will also need the proper ECU for the correct year, motor, and transmission type as they are all different. GTE ECU's for instance have timing and fuel maps that are designed for boost, GE's don't.
Also take note that they changed the wiring harness in 1989, so there are two styles. 1) 1987-88 and 2) 1989-1992. So, if you get a wiring harness from a 1990, Turbo, Automatic car. You'd need the "89+, GTE, A/T" ECU, if it's from a 1987, Manual, Turbo "87, GTE, M/T" and so on and so forth.