Cobb has publicly said that Canadians should use the ACN gas due to our sub-par "premium" gasoline.
I had knock with Cobb's regular 91 OTS map on my STI, running Shell 91. no knock with the ACN map with Shell 91 or Husky 94. I saw knock on the ACN map running Esso, Husky and PetroCan 91.
if you want to run the regular 91 OTS map, I suggest using Husky/Petro/Chevron 94. regardless, datalog