Spark plugs. Why is it so hard?

Spark plug brand choices is a bit like condoms....you buy your favourite brand.
I have always liked NGKs which was one of the few brands that would last in the early Honda 750 m/c engines. Lucky to make it around the block with Champion R6s...

But I digress, ah memories....

NGK heat range for a Mopar V8 is a '5'. Unless it is at WOT for long periods, has nitrous or other power adder.