I have just over 1100 miles on my X3 and in normal driving it has the feel of a "brick" under the gas pedal when you start out. In Sport mode it feels quite peppy. My dealer says BMW's "drive by wire" system cannot be adjusted like Porshe or Volvo---"you'll get used to it!"

Elsewhere on this Forum I read (and tried) a gimmick where you turn the ignition key ON (don't start)---hold the pedal to the floor for 25 seconds--release the pedal--and start the car. Definitely an improvement but still not "crisp"---on a $45K car, I feel disappointed. Wish I had bought the 328xi instead.

When you coast to a stop sign, I can feel the trans downshifting as well?

Is all this normal? Any fixes?

Downshifting is normal. Automatics can only downshift one gear at a time.

There is an SIB for this problem on 2007 X3's manufactured between 08/06 and 04/07. It involves an update to the programming.
SIB 24 08 07 There is a large thread on this issue over at bimmerfest.