For 2016 models we step down 1 heat range in the spark plug which helps prevent unwanted detonation under higher boost pressures.  2017's come with lower heat plugs from the factory, but they protrude into the cylinder further to compensate for the thicker head gasket.  We found that going with the shorter plug on 2017 models also helps prevent detonation and/or pre ignition.  This is a great add on for anyone running AA's tunes on their XPT.  All plugs come pre-gapped to our specification.