An improved multi-bolt or nut torque wrench system for installing or removing a plurality of threaded bolt or nut members on a riser, the system comprising: (a) a plurality of torque stations, each torque station including: (i) a wrench body that includes first and second end portions, and a drive head on the first end portion of the body; (ii) a high torque wrench operatively connected to the drive head for rotating a threaded bolt or nut member at a first rotational speed under a high-torque condition; (iii) a low torque wrench operatively connected to the drive head for rotating the threaded bolt or nut member at a second rotational speed that is a higher rotational speed than the rotational speed of the high torque wrench; (iv) a horizontal positioning mechanism for moving the drive head in a generally horizontal direction; (v) a vertical positioning mechanism for moving the drive head in a generally vertical direction; (b) a source of pressurized fluid that drives the plurality of torque stations; and (c) a controller that controls the plurality of torque stations, including the high torque wrenches, the low torque wrenches, the horizontal positioning mechanism, and the vertical positioning mechanisms such that the plurality of drive heads simultaneously engage their respective bolt or nut members. (a) a plurality of torque stations, each torque station including: (i) a wrench body that includes first and second end portions, and a drive head on the first end portion of the body; (ii) a high torque wrench operatively connected to the drive head for rotating a threaded bolt or nut member at a first rotational speed under a high-torque condition; (iii) a low torque wrench operatively connected to the drive head for rotating the threaded bolt or nut member at a second rotational speed that is a higher rotational speed than the rotational speed of the high torque wrench; (iv) a horizontal positioning mechanism for moving the drive head in a generally horizontal direction; (v) a vertical positioning mechanism for moving the drive head in a generally vertical direction; (i) a wrench body that includes first and second end portions, and a drive head on the first end portion of the body; (ii) a high torque wrench operatively connected to the drive head for rotating a threaded bolt or nut member at a first rotational speed under a high-torque condition; (iii) a low torque wrench operatively connected to the drive head for rotating the threaded bolt or nut member at a second rotational speed that is a higher rotational speed than the rotational speed of the high torque wrench; (iv) a horizontal positioning mechanism for moving the drive head in a generally horizontal direction; (v) a vertical positioning mechanism for moving the drive head in a generally vertical direction; (b) a source of pressurized fluid that drives the plurality of torque stations; and (c) a controller that controls the plurality of torque stations, including the high torque wrenches, the low torque wrenches, the horizontal positioning mechanism, and the vertical positioning mechanisms such that the plurality of drive heads simultaneously engage their respective bolt or nut members.