The Perrin Transmission Mount Support reduces drivetrain movements under hard acceleration, deceleration and corning, which allows your engine to transmit more power to the wheels. This means better, more accurate launches for drag racing and auto cross type events where you do not want drivetrain slop. The factory "T" shaped interlocking support does not fit snugly into the transmission mount. The gaps around this "T" shaped piece allow the transmission to move roughly .500" in all directions. The PERRIN Tranny Mount Support is a larger version of the factory piece, eliminating the gaps and reducing transmission movements. The PERRIN Tranny Mount Support, will only allow .100" of maximum deflection keeping the back end of the tranny in place during extreme driving and giving the driver a positive shift feel. The Perrin tranny mount support pieces are made from CNC'ed 6061-T6 aluminum which means nothing will wear out and no urethane which will eventually squeak!