[davidimurray]

I have a slightly different take on this - just because a part is a replacement it does not mean it is spec for spec an equivalent. No 2 in my list says Trade name AND trade description. Hence I think that unless the leads are actually marked how can the IVA inspector confrim that they are suppressed (a bit like the issues around fuel filler hose). The safest option is to get something that has markings on it - a quick look around the net and the NGK site shows there are a couple of standards ISO 3808 and 6856 for spark plug leads and suppression.

I think the best option is to get a set of leads with an ISO code and the word suppressed on them if possible.