[eleven11]

The M5 is a wonderful vehicle, but if you're even questioning the MPG, I'm not sure it's the right car for you. To actually answer your question, if you're driving conservatively at the speeds you've listed, expect the 20-25mpg range. Actually driving the M5 properly, you're going to see your MPG drop considerably.

I cannot comment on the xDrive question, but other here have in the past. The M5 can be challenging off of the line to gain traction, but it can be done.

Regarding the Competition Package (ZCP), this has been discussed numerous times (do a quick search). Personally, I'm happy I chose it (appearance, slightly better exhaust note vs stock, slight power bump), but it is not a good value.