The Scosche OEM Amplifier Adapter is a non-electronic interface package that allows you to integrate a high-powered aftermarket receiver into select 1990-up Nissan and Infiniti vehicles with premium factory systems. The package includes the OEA-4 adapter and a Nissan-specific harness. The OEA-4 unit has output-level gain controls for each of its four channels which can be adjusted to properly match the new receiver to the factory amplifier.
Was used in my 1990 Nissan 300ZX Twin Turbo and works great. Retails for $39.99 at Crutchfield:
