Exterior additions to the car include numerous carbonfibre styling upgrades, including extended side blades, while a new three-piece rear bumper now incorporates carbon dibble as well. A more aggressive rear diffuser is also fitted.
Available in three colours, the car sits on ten-spoke lightweight alloy wheels, which McLaren says saves four kilos of weight over the standard units.
Inside, the MSO special gets carbon black leather and Alcantara trim with carbonfibre detailing, with a unique plaque denoting the car.
There's no engine upgrades on the car, which means driver's will get the same 3.8-litre twin-turbocharged V8 engine and seven-speed dual-clutch automatic transmission as the standard car. Whether MSO's additions will have any impact on the standard car's 0-60mph sprint time of 3.0 seconds remains to be seen, but the car will be in action on the Goodwood hillclimb this weekend.
The car has been directed under McLaren's design boss Frank Stephenson, and as such each model comes with a signed sketch.
Deliveries of both the coupe and spider models will get under way before the end of the year. Prices start at £252,500 for the coupé and £272,500 for the spider.
McLaren had previously promised to introduce two new models at the Festival of Speed. The second car is believed to be a 650S fettled by the McLaren GT, the division of the company responsible for producing the old 12C GT3 racer. With the 12C now axed, it's only logical that the firm would present a new GT3 race car based on the 650S.