1987 Buick Regal Coupe

The GNX happened because then-chief engineer Dave Sharpe, Buick Advanced Concepts manager Mike Doble and project engineer Chuck Jensen set out to build 'a Grand National to top all Grand Nationals to celebrate the end of its run.'

Buick teamed with ASC/McLaren to avoid disrupting normal engineering and production and worked hard to make it not just faster but substantially better than the 1987 GN on which it was based.

Improved engine controls, freer-flowing heads, low-restriction exhaust and upgrades to the Garrett AiResearch turbocharger - including a lightweight, faster-responding ceramic turbine wheel - boosted output to a muscular 276 horsepower and 360 lb.-ft of torque. The body was stiffened, the rear suspension redesigned and the wheels and tires upsized to 245/50VR16 front and 255/50VR16 rear on special 16-inch alloy wheels to handle that torque and improve stability.

Also added were a transmission oil cooler, composite fender flares and Stewart Warner gauges in a modified cluster. Functional front fender louvers helped lower under-hood temperatures, the all-black exterior was set off by bold GNX badges on the grille, decklid and wheel centers, and each GNX got its own built-date number on the passenger-side dash.

There were only 547 examples of the McLaren-modified GNX models ever built, and these were one of the fastest production cars built in the 1980s. A larger turbo, intercooler and external body/wheel modifications separated it from the Regal GN models. The Buick Regal GNX could easily reach 13-second quarter-mile times and driving home on the highway with the air conditioning on while maintaining 23 mpg.

Some dealers who got one of 547 GNXs built chose to keep it, while others charged as much as $20,000 over its $29,290 sticker price. One reportedly sold for $75,000.