I think i need to change the plugs and leads. Any tips for doing this job? and also suggestions on what plugs or leads are a good brand to buy. thanks
Standard Holden leads are fine. Bosch, NGK Champion or most well known brand plugs are fine also. Pull the leads of the plus by the boots, don't pull the lead. Twisting the boots as you pull will help. Remember what lead went where. Don't over tighten the plugs they don't need a lot of force.
don't forget the black flexible conduit that helps to protect your leads from the heat and consider the genuine leads with the metal boot covers.
Should be able to reuse the metal covers, assuming they're already on there. That's what I've always done anyway.