Colder Spark Plugs

[Tom's Si]

I've got a full bolt on NA build. I've acquired a set of NGK 1422's, the one step colder used in the Evo's. Will it hurt anything if I use them?

 

[webby]

Ngk says only use one of their colder plugs if you're 70-100hp above stock.

 

[Tom's Si]

Thanks Webby.