I found one little difference.

i put the nav by myselfe to my car, and bmw told me it does'nt fit, because i have a low IKE. now it work's, but i can't change settings like the clock, the date, speak, memo, degrees celsius/farenheit and some other things, which does'nt really matter.

now with v27 i can change the speak from german into english or france... cool...