BWK adds one more idler to the system changing the route of the belt that wraps around the supercharger pulley. Oem design is faulty with minimal surface area for the belt to grab on, resulting in belt slip and boost loss, not to say about inconsistent tuning caused by the very fact. By changing the belt routing we were able to add 130% more surface area for better friction. 
 
Fully stock pulley setups have been tested to add 1-2psi of boost. This is an absolute must with smaller supercharger pulleys.
 
The kit comes with brand new heavy duty belt. Please specify your supercharger and crank pulley sizes for the right belt to be included.