Porsche’s already working on the new 718 Cayman GT4, which will reportedly use the 911 GT3’s naturally aspirated flat-six, albeit in a slightly de-tuned form.

However, if you’re the proud owner of the outgoing model, whether the “normal” or the Clubsport version, and you would like to squeeze more power without turning to supercharging or turbocharging, then you might want to consider taking a look at DeMan Motorsport.

Based in New York, the shop is offering a few upgrades for the Cayman GT4 and Cayman GT4 Clubsport, which include an increased engine capacity from 3.8 to 4.25 liters.

The flat-six also gets a new crankshaft, custom pistons, stronger connecting rods and an ECU-tune, which have lifted the output to 488 hp (495 PS / 364 kW) and 360 lb-ft (488 Nm), according to RoadAndTrack – and those numbers have been measured at the wheels.

At the crank, it’s believed to put out 176 hp (179 PS / 131 kW) and 105 lb-ft (142 Nm) of torque more than the stock engine. Also, with those upgrades, the redline has increased to 8,000 rpm, and can be upped by an additional 500 rpm with titanium internals.

There’s a catch though, as the engine upgrade doesn’t come cheap. It costs $28,500, and that’s without the free-flowing exhaust and Cobb access port, which are mandatory to extract the aforementioned output.

Despite the steep price, DeMan says that Cayman GT4 owners have already updated other aspects of their rides, so the cost shouldn’t be a big problem.

This isn’t DeMan’s first upgrade for the Cayman GT4, as they used to offer a 4.0-liter kit, but these new offerings are superior in every aspect.