I know someone who works at the Chysler proving grounds and says the 300C/Magnum RT are very similar to the 5-series in the handling department. This guy was very impressed, and I take his word seriosuly as he is a great SCCA regional autocross driver.
I read an
Autoweek article on the 300C. They were getting high teens in the city and up to 30mpg on some highway stretches according to the on-board computer. also, foud
this Autoweek article on the Magnum.
I don't know for sure, but suspect the Hemi requires mid-grade fuel like it does in the trucks.
I like it. It's on my list of next potential vehicles. I suspect the Magnum sales will lag expectations until a sedan (Charger) comes. Wagons don't sell in the US. Maybe in a year there will be decent incentives on it.
If you are really interested and your dealer can't work on a a decent price, I can get you a friends price, maybe even an employee choice discount.