1. Mileage. Get used to it. Serviced well, and maintained with quality fluids will get your mileage up around 12mpg (if driven normally) in the city. I've clocked over 18mpg with majority highway, and right now I'm sitting at 16.5 mixed driving.
I keep Power Mode on, and I don't launch away from stoplights. Also, I drive in 3 (as opposed to D) around town.

2. Sounds like your programmed for passive arming. Download the alarm reprogramming info sheet from Tone's website and review.