Dodge Challenger 8spd auto claims more mpg than the 6 spd manual - the auto has a facility to shut off four cylinder on constant low throttle - activates them instantly when you deck it - I couldn't tell when it was operating, although others claim to.Is that with the newer 8+ speed autos?
I heard they are very good compared to the older ones.
Although the system is blamed for premature cam follower failure and associated cam lobe being destroyed rather earlier than you might expect, slightly negating the money saving of an extra mpg or several.
I bought the manual as it is rated something 5bhp more Sat in the station car park the other day, engine running, waiting for her train to arrive and deliver her home, I noticed the mpg display ticking down 0.1mpg fairly regularly . . .