[porken]

I have those chips in my '86.5. The ignition chip gives the most benefit, the fuel adds a little up top, but overfuels somewhat on acceleration.

A good setup is the performance ignition with the factory fuel chip. If you are not driving too aggressively, you could use Plus, especially if you plug in the octane loop.

The factory was conservative on the ignition because there are no knock sensors, and they were concerned about the quality of unleaded gas available at the time.