On my Super-Charged engine(which makes over a 1,000 Streetable RWH) my CR is 10.7-1 and I'm almost positive on the Turbo engines they stay at 10.7-1 also.I would talk with what they now call Tuners that work on the Super-Charged & Turbo engines.The Turbo & Super-Charged engines have come a long way in the last few years.