Re: MPG vs W/S (auto) & 2nd in 6spd?
I can't comment on the autostick (the SRT6 doesn't count), but I generally drive my roadster on the highway and get anywhere from 27-29 mpg running 70+. And there are usually short runs of up to 90-100 mixed in. I did one trip of ~150 miles at 55-60 and calculated almost 31 mpg. All this is non-winter driving.
I do accelerate gently - usually in the 2000 rpm range -- and start in first, but skip 5th. It has plenty of torque and by the time I'm going 40 mph it's just easier to slip it from 4th to 6th.
My son tends to make a lot of short, around town trips in the 2007 and gas mileage looks to be in the 18-20 mpg range. But when we picked up the car in Chicago and drove it the 170 miles back home, it got a solid 28+ mpg.