and didn't need to. I pulled the NGKs out after 15,000 miles of hard use (lots and lots of nitrous), decided I'd put in a fresh set of them, gapped at .032. So I start pulling the plugs out...definitely didn't need to change them. There was no gap erosion, the firing tip still had 4 nice hard edges on it (the V groove was still perfect), and the ceramic was clean as hell.
So...moral of the story is that a set of NGK BKR7Es (proably 6Es too, for that matter) will probably last you 30k, no problem even when spraying.
So...moral of the story is that a set of NGK BKR7Es (proably 6Es too, for that matter) will probably last you 30k, no problem even when spraying.