Is the Porsche 911 a good investment?

The thesis

The 911 R is Porsche's purist masterpiece: naturally-aspirated 4.0L flat-six (500 hp), six-speed manual, lightweight GT3 RS mechanicals in a sleeker, more usable body. Limited to 991 units globally, it was the sendoff for the naturally-aspirated 911 GT engine before the 992-generation turbocharged everything. Initial dealer markup frenzy (cars listed at £300k+ over MSRP in 2016) cooled, but values have stabilised in the £320–450k range as the market recognises its last-of-breed status and manual gearbox rarity.