The quest for the "ultimate" in replacement clutches has brought UUC to abandoning all commonly-available aftermarket brands, and instead focussing on a development relationship with the best street and race clutch manufacturer available.The result is a level of quality and performance beyond anything else available.UltraSmooth Cerametallic is ideal for street use and track use and is suited to the high-torque demands of supercharged or turbocharged cars.This clutch's engagement characteristics and pedal effort are the same as a BMW OEM clutch, very smooth and easy to modulate.Note: this clutch contains a sprung-hub center, making it an ideal match for aftermarket flywheels to reduce gearbox rattle.Big news for 6-speed owners! Many M3 6-speed owners have experienced mushy clutch feel, inconsistent engagement, and premature wear of the clutch in their manual-transmission cars. The reason is quite simple - the original BMW (LUK-manufactured) clutch in the E46 has a new "SAC" (Self Adjusting Clutch) design. This new mechanism built into the pressure plate is supposed to keep the clutch pedal engagement point the same as the clutch wears... but in all reality, it's a case of "an answer to a question that nobody was asking." They have added a layer of complexity and feedback isolation, filling a need that didn't need filling - it is not too often that anybody notices that their clutch engagement point as moved 1/2" over 50K miles. The SAC mechanism itself causes problems; it over- or under-adjusts the pressure plate and therefore causes the clutch to slip or burn out prematurely. They are also known to shift, causing the pressure plate release fingers to slip off the plate, keeping 1/3 of the pressure plate engaged at all times. Bottom line is that the only fix is a complete clutch job, and your dealer is likely to claim "driver abuse". We have seen it happen too many times. The SAC mechanism may not give a clean release like a standard clutch. Instead of just two sets of springs, there is an adjuster mechanism that makes engagement feel mushy or slow. The UUC clutch eliminates the SAC mechanism and restores traditional clutch feel with predictable and crisp engagement. This clutch has several advantages for the enthusiast driver: Direct-fit clutch does not require special flywheel.Greater clamping force than standard 3-series clutch.Elimination of the SAC mechanism.Incorporates a sprung-hub design for quiet operation with a heavy-duty steel pressure plate.