The concept car was fitted with a 5.0-litre supercharged AMG V8 engine able to generate a power output of 565 PS (416 kW; 557 hp) and 720 N⋅m (531 lb⋅ft) of torque at 4,000 rpm, mated to a 5-speed automatic gearbox with Touchshift control.

In order to give the car the performance that Mercedes wanted, McLaren had to radically alter the concept for better weight distribution, including moving the engine almost a meter back and lowering the fuel tank.

[1] Smaller adjustments included more complex vents on both sides of the car, a redesigned front with the three pointed star plunged in the nose and red tinted rear lights.

Due to the automatic gear box, front mid-engine arrangement, and its driving characteristics, some automotive journalists classify the SLR McLaren as a grand tourer.

The SLR features active aerodynamics; there is a spoiler mounted on the rear integral air brake flap.

Due to this, there was no other place for the exhaust pipes to exit, other than the sides of the car, making it another unique feature of the SLR.

The Lysholm-type twin-screw supercharger rotates at a maximum of 23,000 rpm and produces 0.9 bar (13 psi) of boost.

19-inch light-alloy wheels were used to reduce unsprung mass, while modifications were also made to the suspension, with a stiffer damper setup and 10 mm (0.39 in) lower ride height introduced for improved handling.

[12] Other exterior changes include red "722" badging, harking back to the original 722 racer, black tinted tail lights and headlamps.

The Roadster's roof is made from a "newly developed material" and does not take the form of a folding metal arrangement, as is common on many modern cars.

According to an official Mercedes document, the cabin of the roadster is capable of allowing conversation between driver and passenger up to a speed of 200 km/h (124 mph) with the roof retracted.

The front grill vents are removed and larger, free flowing air extractors sit on the hood and flank the side of the car.

The engine remains in relatively stock specification but now generates a power output of 680 PS (500 kW; 671 hp) and 830 N⋅m (612 lb⋅ft) of torque at 1.75 bar (175 kPa) of boost and is equipped with a new racing filter and exhaust system.

An adjustable wheel camber along with shock absorbers with variable compression and rebound settings allows the suspension setup to be configured for different race tracks.

New 18-inch OZ racing wheels with central locking nuts allow for faster tyre changes while a pneumatic jack system aids further in the process.

New carbon fibre door panels, plexiglass windows and a full roll cage complete the transformation.

[18][19] The SLR "Crown Edition" was commissioned by the King of Bahrain as gifts for fellow Arab royals.

The car is approximately 200 kg (441 lb) lighter than the regular model due to carbon fibre construction and speedster styling.

The McLaren Edition is based on all variants of the SLR with the exclusion of Stirling Moss and includes revised bodywork (front and rear bumper, grille, top shell, side grills, rear diffuser, wheels) and interior parts, along with upgraded steering and suspension components and a new titanium sports exhaust.

The project was said to be inspired by collectors, who often owned 3 or more SLR's, asking to send their cars back to MSO to receive upgrades or spec changes.

The SLR by MSO upgrade cost £131,500 and features a unique front splitter that looks visually similar to the one found on the 722 edition.

[27][28] Reports suggest that 12 of these cars will be built with each one having unique touches catering to the owner's specifications, costing $350,000.

[37] Spencer Pumpelly entered an SLR McLaren in the Speed World Challenge GT class, driving for TRG Motorsports.