Renntech Mercedes-McLaren SLR 722 PKG2 boosts output to 740HP

When Mercedes decided it was time to give the SLR supercar a boost, it created the SLR 722 edition. The odd labeling of the special edition model caused many to believe the '722' number represented the horsepower output of the car’s supercharged 5.5L V8 engine, while others believed the car’s production would be limited to just 722 units. But they were all wrong. The odd title in fact comes from the 1955 Mille Miglia, where Stirling Moss and Denis Jenkinson beat out favorites from Porsche and Ferrari to take victory in a Mercedes-Benz 300SLR. The car was wearing the number “722,” which indicated the 7.22am starting time of the race.

Last year Mercedes tuner Renntech set about ending the confusion by boosting the output of the supercar to 722hp (538kW) – up from the regular 722’s 650hp (485kW). The original PKG1 kit included upgraded intercoolers, a larger crankshaft pulley, and custom ECU software to reach that power level.

The Florida-based tuner has now released its PKG2 kit and this time power has been boosted to 740hp (552kW) at 6,400rpm. The car has also been given a slight visual update with Signature 10 spoke wheels in SLR offsets and 3 finishes.

Pricing for the standard PKG1 starts at $12,990, while the PKG2 kit will set you back $26,990. Renntech also offers bigger 20in wheels for $1,950 each and owners also opt for more powerful brakes at additional cost.