Equalizer was a separate option according to this brochure----http://www.lov2xlr8.no/brochures/ford/87m_15.html
Yes, it was separate from the Premium Sound option. My above post may have been somewhat misleading.
The equalizer option also changed the radio, so an upgrade requires not only the eq but the cassette radio, and, I believe, some electronic doodads that are part of the wiring harness.
It's a somewhat unusual option. I was disappointed when it was not delivered with one.
It also didn't come with the rear axle ratio I ordered. Supposedly another shortage of parts.
