[Mike]

The reason you put them in is to stiffen the engine mount points so that essentially the power that you are making is not going into moving the engine but moving the car , in a car with rubber mounts some of the engine power goes into acutaly moving the engine in the car on the mounts , the stock rubber mounts offer a nice dampning effect , so that shifts are not as harsh , putting the poly mounts in will stiffen these mounting points up and direct the energy that would otherwise move the engine on the mounts into putting that power into the chassis and drive train, so your shifts will be much more crisp enabling faster shifts.