SP Engineering recommends using NGK spark plugs for any RB26 engine build. NGK plugs with a heat range of seven or eight are a good choice for those who have an engine with minor engine work or turbo upgrades. For drag racing applications SP Engineering recommends going with a nine- or 10-range plug and everyone should stay away from iridium and stick with platinum plugs. The more serious plug used in F1 Racing, World Rally Championship, and MotoGP is the NGK race plug, which lacks an electrode tip that would otherwise break off or melt from the severity of the engine. These are the highest-level spark plugs that NGK has to offer.