Outwardly, the new engine casings differ from the other 996s in the redesigned oil sump, which is deeper, and in the layout of the external head lubrication pipes. 

Inside, bore and stroke dimensions have been increased from 98 to 100 mm and from 66 to 63.5 mm respectively, for a more aggressive ratio that - combined with the racing trim - allows for higher speeds than could be reached with the previous configuration. The most innovative element, however, is the combustion chamber with its compact profile due to the revised geometry of the timing system components. The valves are arranged at an inner angle of as little as 25°, compared to the original 40°. 

Inner valve diameter has been increased from 38mm to 40mm, whereas the exhaust valves remain unchanged with a 33mm diameter. 

Intake and exhaust pipe geometry has been re-designed as well, and now features a straighter configuration. 

The new heads developed for the 996R assure greater volumetric and thermodynamic efficiency as evidenced by the output power of the road version engine: 135 HP (101Kw) at 10,200 rpm. 

Compared to the 2000 996SPS, the 2001 996R puts out an additional 13 HP at 200 rpm less.   The relevant torque curve shows a more regular and progressive trend at the same peak values. And that's not all. 

The fuel system is operated by a Marelli integrated digital system featuring an ultra-compact, extremely light, latest-generation 5.9 M CPU, which means smaller, lighter and less complicated wiring. This CPU offers greater calculation capabilities than the previous one, with additional features such as cooling fan control. 

The injection system is similar to that of the 748R, normally used in F1, composed of a single "shower" injector at the centre. 

The ignition system uses stick-coils placed directly on top of the spark plugs. 

Beside the significant power advantage, coupled with amazing acceleration and a seemingly unending power curve, the 996R also runs notably quieter than its predecessor. This is one more virtue that purists will not fail to appreciate.