This 1990 Nissan 300ZX is said to have been modified in the early 1990s by Stillen of Costa Mesa, California, with updated body panels, Stillen Sport 500 aftermarket turbochargers and intercoolers, an HKS turbo timer and blowoff valves, a Stillen full exhaust system, Simpson four-point racing harnesses, 17″ Antera three-spoke chrome wheels, and modified brakes and suspension. Power comes from a twin-turbocharged 3.0-liter V6 paired with a five-speed manual transmission, and the car is finished in black over…