General guidelines for tuning GM vehicles:

2005 SOFTWARE A. All 2005 supported vehicles, including CTS-V Uses .CR3 or .3CL file formats, 3CL to be used in Predator only. 2005 SOFTWARE B . Most recent update from GM for 2005 models. Uses .CR3 or .3CL file formats, 3CL to be used in Predator only. 2006 SOFTWARE A. Early 2006 calibrations Uses .CR3 or .3CL file formats, 3CL to be used in ... ................
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