While MINI may have given Gen 1 Cooper "S" owners a literal boost over standard Coopers, there is no reason to be comfortable with 163HP. Turn up the power with a smaller supercharger pulley. The ALTA Performance 15% reduction supercharger pulleys do just that. With the simple installation of this pulley and no other modifications, you will raise boost 3-5 psi and more than 20WHP.
With a 15% pulley this rise in boost pressure will increase 15 to 20 horse power. No other modifications to ECU etc required.
ALTA Performance was the first manufacturer to design a two-piece, taper-fit Mini Cooper Supercharger Pulley. Today, it is the most imitated design on the market. Now they've upped the ante with the ALTA Performance™ Version 2.0 Supercharger Pulley. The new pulley features a stainless steel supercharger shaft coupler with installation site aperture and the first to offer direct torque technology. Ultra-light aluminum body decreases rotational inertia and overall weight. Over-sized belt retainers and belt groove teeth increase belt grip. A decorative end cap faceplate provides a clean sleek look.