The automatic also has the MDS . Think that's right. Where it will drop back to 4 cylinder's above 60 mph cruising . A Chrysler engineer said the reason the 6 spd does not . Is because they couldn't compute what gear the trans would be in as with the computer controled automatic. So the 6 speed engine run's on 8 all the time . And that was the answer to that question in Hot Rodding by the Chrysler engeener . I have a 300C automatic that does run on the 4 sometime. I'm happy with my R/T running on 8 and get better gas mileage than my wife's car most of the time.