What affect if any if silicone IS NOT used beneath the ignition coil pack?

silicone is a good electrical insulator...the coil pack needs to be immobilized with some kind of cradle...normally a single bolt up the middle is on a "cradle" and should not need any silicone unless you're in a vibration filled environment~

Thanks for your reply. What type of silicone is recommended? I am experiencing an engine vibration more severe at times than others and read that silicone beneath the coil would help eliminate the vibration.

THANKS >>>The answer I was seeking is a substance called dielectric grease>>>>after its application the overall performance of the vehicle has improved.

RTV----room temperature vulcanizing silicone rubber works and is OEM on many parts of your car~