At first glance, this 911 speaks of subtle perfection. But then all 911s of this air-cooled era do. Always worthy of sigh and a wish of admiration. But look closer and you begin to see that this Porsche is way more than standard perfection: with a lowered, measured stance, a glimpse of a racing roll cage through the windows. Then there's those not-quite-Fuchs alloys. And a distinct lack of anything that's extraneous. Except perhaps its name: this 911 answers to Dirk.

At Accumoto in Wisconsin they have a habit of naming the 911s that they lovingly rebuild to owners' specification and usually to the standards of the race cars that they construct and prepare for customers. Lucille for instance is bright orange. Dirk takes the quieter approach. At least until you fire up the entirely rebuilt and reimagined flat six under the rear lid, and that's when things get very loud indeed.

Dirk was the prototype build for the Accumoto set-up, run by 911 enthusiast Mark White, and so carries "0000" as its build number on the bespoke Accumoto build plaque just inside the driver's door. That plaque says a lot about Dirk and the way Accumoto work. While the basis is recognisably a 911, so much has changed. Inside, for instance, there's that full race roll cage and two black leather bucket seats originally designed for a 996-series 911 GT3. Those not-Fuchs alloys? Designed and manufactured in house. Momo steering wheel has yellow centring stripe. On track, you'll be thankful.

White finish was applied after a full strip down of the body. Also stripped down: the flat six. Now boasting Pauter connecting rods, EBS valves, bored out cylinders with JE pistons and a five speed short-ratio manual transaxle - take note of the beauty of the minimalist open gate shift inside - the Porsche is good for 300 bhp. Fun to drive? We'd bet the house on it.

"There was no money spent," say Accumoto, "that wasn't towards making it a driver's car." Drilled door handles save weight. Central mounted fuel filler to front lid is in the racing style. Cross drilled brake discs ensure you'll be stopping as well as accelerating at breakneck speed. And perhaps our favourite interior feature: the electric window controls disguised as manual winders.

So what you're seeing here is effectively a bespoke build, a one of a kind 911 that's barely run in and is now ready for a life outside an air conditioned collection. Happily, Accumoto's work is very much under the radar so there's no style shouting here. But naturally all of these specialist hours of work come at a price. The nice people at Classic Driver have a price of a quarter of a million US dollars on Dirk the 911, or £187,000. A bargain when you consider all that attention to detail.