A Careful Nudge at Perfection
The Nissan 300 ZX has haunted our hit lists since 1989 arrived. Three hundred ponies. Looks that refuse to date. A chassis that balances comfort with control without breaking a sweat. It is a versatile sports car. A genuinely good one.
But what do you do with perfection?
You want more power? It doesn’t really need it. New styling? Maybe, but too much surgery ruins the elegant underlying DNA of the Z. Better handling? It already turns like it’s on rails. The two-position shocks on “sport” setting are already fierce.
So how do you tweak a car this well-cooked?
Very carefully. That seems to be Stillen Motorsport’s philosophy with their SMZ project. Founder Steve Millen has been modifying Nissans for years, racing them into the ground and back. We drove his 1992 convertible conversion previously, noting many of the same aesthetic cues.
This coupe, however, is different.
The SMZ is not a backyard special. It was developed in cooperation with Nissan’s North American division to sell directly through dealers. Full factory warranty attached. A premium of roughly $14,00 over the stock Turbo model.
Looks: Subtle, With a Wing
Ignore the large rear wing for a moment. The exterior changes are actually quite restrained. Even the wing is more functional than the original low spoiler. The stock design blocked rearward vision; this one does not.
The rest of the face lift includes mock-louvered nose panels. Aggressive front splitters. Voluptuous rocker panel and rear valence cladding. Yokohama wheels complete the picture.
Inside, the carbon fiber appears on door handle surrounds, the center console, the shifter knob. Slide in, and your eyes catch the alloy pedals. They look sharp. They help with heel-toe downshifts. But a size 11 foot tends to accidentally blip the throttle when braking. An annoyance, minor as it may be.
The Breath of Power
Turn the key. The modifications announce themselves.
A new intake manifold. A new air filter. The engine breathes deeper. The aluminized steel exhaust system flows better, replacing the stock note with a more authoritative burble. Stillen added 2 psi of boost pressure.
The result? Sixty-five additional horsepower.
Drivability suffers zero casualties. Ease off the clutch, and the car moves with docile grace. It will pull away happily from a stop in second gear. Flexibility remains intact.
But lift into the rev range. Full throttle launches generate tire smoke. Axle hop. Furious acceleration. On any surface that isn’t perfectly smooth, that extra two pounds of boost will spin those rear tires in second gear. And we say that despite 275-section Yokohama AVS tires wrapping around 9.5-inch rims.
The midrange feels distinctly muscular. The onset of boost is faster. High-RPM thrust is emphatic.
Numbers confirm the feeling. Zero to sixty is 0.3 seconds quicker. The quarter-mile time drops by 0.2 seconds with a top speed increase of 1 mph. Modest gains. Until you check the rolling tests.
50 to 70 in eighth gear? The SMZ posts 8.2 seconds. The stock car needed 8.9. On the highway, throttle response just feels quicker.
Chassis Control
Stillen didn’t mess with the shocks. The original two-position unit remains.
What changed? Springs. Stiffer anti-roll bars. Higher-rate springs tighten the body control significantly. Skidpad numbers climb to 0.92g, up from the standard 0.89. One tester called the limit “excellent… uncommon for a tuner car.”
The chassis amplifies the Z-car’s rapid off-center steering response. The car tracks like a train on smooth tarmac.
Until the ruts appear.
Driving here in Michigan, with wide 255-width front tires hunting for grip in asphalt gullies, the SMZ darts like a prison bloodhound. It jumps and jinks.
Road feedback transmits more abruptly thanks to the stiffer setup. We found it acceptable for a sports car. At speed, the stiff body and intelligent suspension geometry still cushion the worst impacts. Leave the suspension switch on “Touring.” Save “Sport” for when you’re truly in a hurry.
The Verdict
The trick to converting the 300ZX? Do not sacrifice practicality. Stillen nailed it mostly.
Weather is still an enemy. The stock 300zx Turbo was never a winter vehicle. The SMZ is worse. Tighter suspension and sticky rubber offer less margin for error when water is on the pavement.
That Z-car habit of stepping out under boost feels more sudden here. The tail swings wider, quicker. Recovery requires the same techniques, applied with slightly more urgency.
Do not play boy racer on wet pavement in a rear-wheel-drive sports car with this much torque. Unless you are Steve Millen. His prodigious driving skill helped tune the suspension for this quick, predictable feel.
Nissan North America would not warranty just any upgrade. This is a factory-approved monster. A rare thing indeed.
What now?
