rotorbloop82

I know this would have been discussed in many other forums, but can't be bothered searching. I've a 12a Stock to the hills, Here in Australia we have 98ron fuel ie: Shell Optimax, Bp Ultimate, Mobil Synergy etc. When my tank is full of normal Unleaded 92ron. I get no backfires at all and suffer with a little powerloss, on the other hand if I fill tank with Primium Unleaded 98ron, she suffers with a few big back fires and a little power gain. So in order to fix this with out adjusting Timing or Air screw(s), I would like to purchase new plugs and coils any suggestion. Engine still running standard electronic SLIDFIS (ignition). I would Like to know: PLUG TYPE, COIL TYPE, LEADS eg:8mm or 10mm. or somebody could give me a good combination on all goodies. Cheers Jay