Will the COMP CAMS to suit Holden V6 Ecotec fit into an Ecotec manual v6 without any problems? If so what stage would Mace recommend-stage1 or stage2?

Yes, the cams will be 100% suitable and there will be no problems in relation to fitment. In order to recommend an appropriate package regarding the stage 1 or 2 we would need to know the customer’s intended use and desired outcomes so that we can advise which one will best suit their vehicle.