The usual disclaimer applies here: the 650S’s standard, option-free sticker price starts well north of £200k, placing it comfortably in the silly-money stratosphere where price tags carry little real meaning and running costs none at all.
A Porsche 911 Turbo S is considerably better across the board. For what it’s worth, we recorded 23.8mpg on a touring run and 18.1mpg as an overall average – the latter being only slightly less than for the 12C Spider.
A careful owner may well do better, but don’t expect to see much more than 300 miles between fill-ups of the car’s 72-litre tank.
In terms of options, we'd go for the sports exhaust and lifter system that raises the nose. Avoid carbonfibre options where they'd get scraped, and don't go overboard elsewhere.