I left mine gapped at stock(.44) when I was BPU and they where great. That will not work well once you go single. With my SP57 boosting to 19lbs, it would blow the plugs out. I had to order new plugs after 2 dyno sessions (about 20 pulls) becuase they are so fouled that my car idles bad. I also had 20k miles on these plugs though.