E55 plugs

[ES5 4 NOW]

Which plugs would be recommended for a tuned e55.
1 step or 2 step down in heat range?
Any part numbers would be great full.

Thanks

 

[Alex]

You usually go one step colder with every 100bhp added.

 

[Cyclone1]

Colder Plugs - NGK LFR7AIX

Normal plugs - NGK ILFR6A

 

[ES5 4 NOW]

Thanks guys.