RE: Hemi Spark Plugs
The reason you only see 8 coils is because each coil fires two plugs at the same time. The system fires one plug on the power stroke, and another plug on the other side of the engine on the exhaust stroke. Its an emissions thing.
Although Chrysler and others have said not to run platinum, I am the rebel and have hadthe platinum equivalent of the OEM plug by Champion in my 4.7 for 40k now. No issues, and the gap is still .040.
I can testify that the OEM plugs were shot at 30k.