The past few generations of Ferrari's mid-engine V8 sports cars have gotten a late-life performance kick that results in a hot new model. See: 360 Challenge Stradale, 430 Scuderia and 458 Speciale. These new models ditch nearly every creature comfort in the pursuit of speed and power. Engines are cranked up, suspension geometry is reworked, and the bodywork is adjusted for aerodynamic efficiency.
While we can't see what's changed under the skin, these prototypes do appear to have slightly different bodywork than the standard 488 GTB. The most notable changes are to the front end and rear fenders. The front intakes appear to be the same size and shape, but the splitter hanging out front looks like it's been reworked. Around to the side, the large air intakes just behind the doors look larger than before. This all leads credence to this being the 488 GTO – especially given the turbo connection between the original 288 GTO and the 488.
Still, this could be something milder, although that's less likely. There's been rumors for a while that Ferrari have been working on a less expensive mid-engine car that will be called the Dino. We've seen other test mules running around that some claim were powered by the Ferrari-built twin-turbo V6 in the Alfa Romeo Giulia. Either way, a new Ferrari is always something to look forward to.