Re: Mpg
I calculate mileage the old fashioned way: miles/gallons after each fill up. Roadster gets about 24-25 mpg in combined town/hwy and an easy 27-29 mpg on the highway (70-75 mph), and once got 31 when I behaved myself and drove 60-70. That has been consistent on three long drives to CT/NY, 800 miles each way.
By comparison, the SRT6 has never gotten better than 24-25 on the highway, but I admit to at least half a dozen high speed runs (~100 mph) for every tank. My son does almost all town driving with his 2007 and gets 18-20 mpg. But he also keeps it in lower gears longer than he should and has a tendency to run right up to lights/stop signs where I will coast in gear and let the engine brake the car.
There's no way the automatic gets better gas mileage if you know how to drive a stick.