The Regal GS sports a front fascia unique to the Regal lineup, the most noticeable bit being its vertical air intakes just below the headlights.
White Frost Tricoat is one of three new colors for the Regal for 2016. The other two are Ebony Twilight Metallic and Crimson Red Tintcoat.
Out back, the Regal GS separates itself from other Regal variants with its integrated exhaust outlets and rear spoiler extension.
While 19-inch wheels are standard for Regal GS models, buyers can opt for the 20-inch alloy wheels you see here, which are wrapped in summer-only performance tires.
The 2016 Regal GS also features a lower ride height than other Regal variants, thanks to a unique set of computer-controlled dampers that make for a much more engaging ride.
Between the optional 20-inch alloy wheels and that unique front end, the Regal GS has an aggressiveness to it that the other variants lack.
The Buick Regal isn't available in UK or Australian markets, but Vauxhall makes several similar variants, high-perf or otherwise, under the Insignia nameplate.
The rear suspension differs, depending on your choice of drivetrain. Front-wheel-drive models feature a four-link rear suspension, whereas all-wheel-drive models sport an H-arm rear suspension layout.
Brembo front brakes are standard for all Regal GS variants.
There are no changes to the Regal's interior for the GS trim, but it's still a soft, comfortable place to spend a few hours.
While European-spec models have an available manual transmission, here in the US, the only option is a six-speed automatic.
Flipping the switch to GS mode increases the Regal GS's steering effort for a sportier driving experience.
As with many other current GM models, the Buick Regal makes use of both physical gauges and a large information screen.
When you're ready to hit the track, GS mode stiffens up the dampers, increases steering effort, speeds up transmission shifting, and tweaks the AWD system's power delivery.
The Regal GS is a blast on an autocross course, but GS mode reduces body roll to a point where it's difficult to transfer weight to the driven wheel that needs it the most.
Despite being front-biased, the Regal GS keeps torque steer to a minimum with a HiPer Strut front suspension that features a unique geometry built especially for front-biased vehicles.
All Buick Regal models, save for the bare-bones base variant, are powered by a 2.0-liter turbocharged I-4, good for 259 horsepower and 295 pound-feet of torque.
When you're not thrashing the Regal GS about on the track, it'll return 21 mpg city and 30 mpg highway in front-wheel-drive guise. All-wheel-drive models make do with 19 mpg city and 27 mpg highway.
Unlike other occasional-track-day sedans, the Regal GS is a relative bargain, coming in at an MSRP of $34,990, a surprising $3,320 cheaper than last year.
(GM doesn't market Buick in the UK or Australia, although similar models are available under its Vauxhall nameplate in the UK. For comparison, the Regal GS' US price converts to just under £22,800 or about AU$47,500 at current exchange rates.)
If you need to get some work done between runs on the track, you'll be happy to know that the Regal GS comes available with a 4G LTE connection and Wi-Fi hotspot capability.
The only thing the Regal GS could use to be better for the track is a louder exhaust. Without being able to rely on engine note alone, it's difficult to avoid banging up against the redline.