Founded in 1967 by a pair of former Mercedes-Benz engineers, the engine builder and independent tuning firm AMG quickly became known for shoehorning large engines into small chassis. In 1994, the company entered a partnership with Mercedes-Benz, which later evolved into AMG’s outright sale in 1999. Co-founder Hans Werner Aufrecht—the “A” in AMG—relinquished his remaining shares in 2005, bringing AMG fully into the Daimler portfolio. Headquartered in Affalterbach, Germany, and now called Mercedes-AMG, the division currently builds its own performance vehicles, race cars, and variants of virtually every Mercedes-Benz model.

This pre-merger Mercedes-Benz S-Class coupe began life as a German-market 500 SEC clad in Blauschwarz (Blue-Black Metallic) over Anthracite leather and was delivered new in September 1985. Badging and distinctive features on the car indicate that it was likely exported to Japan via the Yanase dealership network, retailed, and then later converted by AMG Japan.

It now sports an AMG 6.0-liter engine, complete with the requisite pair of proprietary 16-valve, sand-cast heads, along with a modified throttle body, ported intake manifold, and AMG by Sebring exhaust. Engine stampings reveal that it is labeled “204”. The block is a modified 5.5-liter unit of European specification.

The coupe’s exterior, with period-correct “Gen II” AMG ground effects, is now clad in Pearl White Metallic. The bespoke interior is an updated affair which features a pair of multifunction Recaro CSE seats trimmed in black and white leather. Burlwood veneers compliment a suite of AMG gauges, an aftermarket Nardi steering wheel, and an Alpine head unit.

At the rear, a reflective trim panel, or “heckblende,” unites the coupe’s distinctive taillights. A set of color-matched, staggered, three-piece 17-inch Style 2 AMG wheels wear Continental ExtremeContact tires. The consignor notes that this chassis retains the stock 500 SEC brakes.

A tool roll, spare wheel, jack, first-aid kit, Japanese manuals, and AMG literature, including owner’s manuals, registration folder, and document pouch, accompany the sale.