Purchased this hydraulic clutch assist and expected the “easy installation” as in the product description. When I received the part instructions stated “to get the full effect the clutch return spring must be removed. . It is recommended this be performed by a certified BMW technician”. This would add another $300 to the cost. I contacted MAGURA and they stated more emphatically that the return spring must be removed for the product to work. I returned the product to Sierra with no issues. This issue is with the product description, NOT Sierra BMW. If you feel competent to remove the return spring, the new clutch may be well worth the money. It was not an option for me.