There is a techie bit on that site I mentioned www.spark-plugs.co.uk
I've got IQ20's in mine, I had to re-gap em to 0.8, my method is to hold the plug lightly and bang down on to a hard surface, but be gentle as if you go too far it's a bit of a job to open em up especially with that delicate little tip
Think im gonna tell them bollocks & to get the ones Pauls got. Not gonna take any chances after reading this from AHAs link.............
You may need to change the heat range of your plug (indicated by the number in the middle of the NGK part code - e.g. BPR6ES to BPR7ES) if certain aspects of your engine have been modified to increase (or decrease) performance. A change of heat range is most commonly needed when increasing the engine's compression ratio. If the vehicle is turbo charged and has had a severe 'boost upgrade' (the turbo wastegate vacuum lines have been manipulated to allow a higher pressure to build up before release) you may also require a colder grade spark plug.
Changing heat ranges
It should be noted that putting a colder grade (higher number=colder grade, e.g. BPR5ES=hotter, BPR7ES=colder) of spark plug in an engine which doesn't require a colder grade may cause difficult cold starting, plug fouling and poor running at low revs. Using a hotter grade (lower number=hotter grade) than is required may be the cause of overheating, detonation and heat damage to both spark plug and combustion chamber components.
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