Fixed supercharger pulleys keep the blower engaged at all times making the car way more responsive to throttle input. Reduced mass in the pulley also makes it easier to spin adding further responsiveness. While mpg slightly goes down and intake temps slight rise during cruising, WOT temps and mpg remain the same as if it were clutched. This pulley makes the car feel like its making the power its making unlike feeling like 300hp car with clutched pulley until you go WOT.
Wide variety of size choses are available from stock to ‘full send’ 65mm.
 
Please make sure you have appropriate cooling, tuning and belt wrap kit when making your size choice.