Thanks to a revised air intake and changes to the turbo, the 2.5-litre flat-four engine now produces 361bhp and 317lb ft torque. Porsche purists will be happy with the gearbox, which is a six-speed manual as standard, with a seven-speed PDK dual-clutch transmission available as an option.
Fuel consumption on both GTS models is 34.4mpg and 186g/km CO2 emissions.
Porsche says both GTS models can run 0-62mph in 4.1sec, en route to a 180mph top speed. Performance is further enhanced with features like the company’s Active Suspension System and Porsche Torque Vectoring with a mechanical rear differential, both of which come as standard on the GTS.
The extra hustle is accompanied by a number of visual upgrades as well – a sport front fascia is flanked by tinted indicators and rear lights. The darker theme is continued with a black lower rear fascia, black exhaust tips, black 20-inch wheels and black badging around each model.
Inside, GTS drivers will enjoy the centrally mounted chronometer as part of the Sport Chrono Package, which is standard equipment. The centre portions of the seats get the Alcantara treatment, along with the centre console armrest, door armrests and steering wheel rim. Seat headrests get embroidered GTS logos.
Prices will start from £59,866 for the Cayman and £61,727 for the Boxster. Porsche says both cars are available for order right now, with deliveries scheduled for mid-December 2017.