The Porsche 911 is an icon whose most loyal fans hate to see altered. While its famous silhouette styling and flat-six engine mounted at the rear have remained constant over the years, the powerplant switched from air-cooled to water-cooled back in 1996 and, more recently, was been turbocharged across the lineup, save for GT models. And it appears that's something 911 fans will have to get used to.

Porsche's man in charge of sports car, Frank-Steffen Walliser told Autocar it is "not really feasible" for any future 911 variants to return to a naturally aspirated flat-six. The 4.0-liter flat-six works brilliantly in the Porsche 718 Cayman GT4 and Boxster Spyder, and was detuned for the Cayman GTS and Boxster GTS, but there's an issue with using it in the 911: it needs to be rotated 180-degrees. Blame the 911's rear-engine layout.

That engineering task alone isn't cheap and combined with upcoming new emissions standards, it's just not worth Porsche's time and money. Walliser admitted a naturally aspirated 911 is something he'd love to see happen. However, "the reality tells me it will not happen," he said. "I would love to do something like that… [but] the research and development costs are too high to develop such an engine for the Carrera." Bear in mind Walliser's words apply only to non-GT 911s.

The next 911 GT3, which was briefly teased in last February's Super Bowl commercial, will retain its NA engine. "Our philosophy in GT cars is to stay naturally aspirated," added GT division chief Andreas Preuninger. The 911 GT3, GT3 RS, and GT2 RS are clearly not for all 911 customers, but they do occupy a very important niche segment within the lineup.

Given their relatively low combined production numbers, it's possible for Porsche to keep them naturally aspirated while turbocharging and electrifying the rest of its lineup. And speaking of electrifying, Walliser provided an update regarding the 911 hybrid, due to arrive later in the 992's production life.

Weight remains the "biggest burden" though this is hardly surprising. Batteries have never been light, but there's another issue to contend with: space. "We have to package everything, because the car is relatively small. We don't want to give up the 2+2 layout, the architecture or the shape of the car, because these are part of the 911 story."

The 911's evolution continues.