I notice that the 300C comes with a 3.07 rear axle ratio. Has anyone put in a 3.64 or other gear ratio? I have done this on several vehicles in the past and have yielded outstanding performance gains. The only problem I foresee is speedometer calibration. Is there something out there that can program a different gear ratio or compensate it in some way? I'm not too familiar with Chryslers so forgive the ignorance.