check all the gaps are the same I think from memory this will be about 30 thou, the critics of splitfires if you haven tried them then you are missing out on a standardish skyline they will give you an noticable increase in low down power due to the fact they burn more of the unburnt fuel that exists in your engines, up to a point they are short of brilliant but unfortunatly due to the fact they have a limited heat range equivalent to about NGK 8 I have personally stopped using them, I ran them to 666 bhp and 515 ftlb torque and was dissapointed when I asked splitfire for a colder plug they could not fullfill my wishes , so adopted the fact that if I could not run them in my car then I should not run them in anyone elses and so STOPPED useing them, I currently run the GREEDY plug which is a NGK as it has full heat range available and was obtained from tim at SVS but am soon to try the HKS racing range of plugs.
Note I had HKS plugs in my car at the time it expired.
Bottom end built
Needed some new plugs (standard car) and have been trying to get some for a while now. Found some local to me at a car spares place. You wouldn't believe the number of places that don't stock NGKR's in the correct Skyline heat range etc. Then when I found some they were between £15 and £17 each!
Still, I now have a handy supplier at £7.94 plus VAT per plug. I believe that this is quite reasonable If anyone else needs them I can give you the number of the wholesalers