Be aware that the silicone pad also usually acts as an electrical insulator to isolate the tab of a heat generating device from ground, yet provide good heat transfer. If electrical insulation was not needed, they would have bolted it straight to the frame, perhaps using paste. So I would not change it unless you are sure it is not also an insulator. My info shows that paste results in a thermal resistance of about 0.8 degree C/watt whereas a dry silicon pad is rated at 1.5. Lower values are better in this instance. The numbers mean that for every watt of heat transferred there will be 0.8 and 1.5 degee C of temp difference respectively.
Rod
