Porsche’s 718 Cayman and Boxster received the GTS treatment for 2018, but this doesn't represent the end of the performance road for Porsche's entry-level sports car.

The German sports car marque is currently working on the next rung up the ladder, the new 718 Cayman GT4 and Boxster Spyder.

Previously thought to be arriving for 2019—instead we got the tamer 718 Cayman and Boxster T—the Cayman GT4 and Boxster Spyder should now arrive for 2020, meaning a debut can't be far. Shown here is a prototype for the Cayman GT4, or possibly a more extreme Cayman GT4 RS. We've also spied the Boxster Spyder in recent months.

The standard Boxster and Cayman are fitted exclusively with turbocharged flat-4 engines, but the more potent versions are expected to run naturally aspirated flat-6 engines, just like their predecessors. That’s the word of Porsche engineer August Achleitner, who headed 718 and 911 development prior to retiring late last year.

The last Cayman GT4, introduced for 2016, came with a 3.8-liter flat-6 good for 385 horsepower. There are rumors this new one will come with more than 400 hp. The latest 718 Cayman GT4 race car is running a 3.8-liter flat-6 good for 425 hp.

What isn’t so clear is whether there will be a dual-clutch transmission available this time, though the option is rumored to be coming. The last Cayman GT4 was offered exclusively with a manual.

2020 Porsche 718 Cayman GT4 spy shots - Image via S. Baldauf/SB-Medien

2020 Porsche 718 Cayman GT4 spy shots - Image via S. Baldauf/SB-Medien

Expect the 0-60 mph time to dip below 4.0 seconds and the top speed to lie somewhere above 180 mph. The last Cayman GT4 would hit 60 mph in 4.2 seconds and top out at 183 mph.

Other upgrades will include lowered suspension, a more aggressive aero kit with larger intakes, plus uprated brakes and sharpened steering. We can also see that the exhaust tips have been moved away from the center of the rear bumper, like on the last Cayman GT4, and more toward the outer flanks. There's also a much bigger rear wing fitted to the latest testers.

Production will be limited, so if you’re interested in parking one on your driveway you better start cozying up to your local Porsche dealer. These special editions typically sell out fast, and the new Cayman GT4, like its predecessor, will likely turn out to be a true collector's car. This will especially be true if Porsche goes ahead with plans currently being discussed about converting the 718 line to electric power.