Brand new (not refurbished) modified ATE power brake booster for use when installing a DOHC e36 / z3 motor (M50 / M52 / S50 / S52) into an E30 3-series 1984-1991. This booster is a direct replacement for the original booster and requires no further modifications. The original master cylinder and reservoir can be used with this booster. It is a smaller diameter then the original to accommodate the larger intake manifold when swapping to one of these larger motors.