The main reason I fitted them is that I don't like buying plugs every 6k,I would rather fit a good set & not have to do it again for 30k.Kinda works out cheaper to pay circa .£45.0 every other year than, £20.0 on std plugs every year,or 6k.Without having a dyno to hand it's hard to check for any physical difference? But I am happy with the way my car performs.It runs very cleanly.It's a good sign of quality, when manufacturers fit them as std.See how many car makers fit splitfires as std?
Steve.