spark plug equivalent

[speedo]

As most sources for spark plug want to know "year, make and model" , it becomes difficult for hot-rodded (read non-conventional) engines to get a good engine-plug match. My spec books list correct original plugs as ...
Bosch W260T and W265P21 or
Beru 260/14/3 and 265/14/3P
Engine is a 2.7 RS spec MFI engine and the plugs in it are NGK BP7ES
Has anyone put together a chart for the various engine configurations and respective correct plugs that are available? Seems like a dark-science to me
And with all the concern about engines burning valves by running too lean, I am going to guess we could be doing equal damage by running plugs that are either too hot, or too cold??

Speedo

[MaRu]

With this engine spec I would take Wr3cc Bosch... maybe a little to cold, but will start fine and you are safe!