Having the fastest production-based car around the 'Ring takes power, poise, and predictability. As an aside, I consider this car a genuine production car that's been optimized and not wildly modified, as the power output remains the same as the factory car, and the right elements of the car have been massaged just so to give the car added performance in several areas—and it still remains streetable and street legal.
Some might disagree with me, but I consider this the epitome of a thoughtful tuning approach, without any need for sensationalized figures. Perhaps nothing raises the eyebrows like a lap time, however—just read "6:40.33" and feel the hairs stand up on the back of your neck.
In any event, the GT2 RS MR benefits from a series of changes that might not catch the casual observer's attention. Manthey was conscious of not touching the engine of the gearbox, as they feel it's easy to ascribe any gains in time to just straightline speed. Plus, as more power is quite easy to extract from a turbocharged motor, gains from setup seem to be worth more in the eyes of the dedicated track rat. That said, they have added another water tank for intercooler spraying, which allows the engine can run at high revs for longer.
To minimize unsprung weight, the MR uses magnesium wheels similar to those in the Weissach Package. Brake pads and upgraded brake lines provide a little more reassurance, response, and endurance. However, the KW suspension is where the magic truly begins. Custom-tailored to the heavyset GT2 RS MR, the dampers are designed to handle the increase in downforce, and are quite similar to their GT3 R, which won the 24 Hours of the Nurburgring and Le Mans. In fact, the engineers from Manthey's racing program were involved in the development of this car.
The aero gains are subtle but effective, and they still remain street-legal. The front end enjoys tiny canards which meet German TUV regulations, a different underbody floor, aero curtains in the wheelarches. To balance the gain in front downforce, a gurney flap on the engine lid, different wing endplates, a larger wing at a steeper angle, taller wing supports, and a bigger diffuser. At higher speeds, these make the car even more reassuring. To demonstrate their depth of thought, they added reinforced decklid hinges to cope with the greater downforce, and they offer some rear chassis stiffening.
It only takes two days to bring a GT2 RS up to MR-spec, and it will set its owners back roughly $108,000—if they choose to buy Manthey's lightweight wheels. It's quite steep for a gain of seven seconds a lap, but it shows how several thoughtful pieces make a massive difference in speed.