The RENNtech SLR McLaren 722 PKG2 is yet another RENNtech-tuned version of the Mercedes-Benz SLR, following in the large-horsepower footsteps of the Mercedes-Benz SLR 722 and the original RENNtech 722. The original upped power from the SLR's base 650 horses to 722 HP, thus reducing the confusion over the name (7:22 am…