When I open the file for this c6 it has a OS upgrade option of 2 bar under operating systems. Bill from hptuner told me by email that the upgraded operating system is 2.5 bar. I have both 2 and 3 bar sensors but do not have a 2.5 bar sensor. I was wanting some clarification on which sensor I should be using and also if the operating system is 2.5 bar.