Increase prius mpg?????????

i have a lancer evolution 10 it gets about 16 city 22 highway which is crappy so im gonna be trading it in for a Toyota prius which is 51 city and 48 highway,,,,,i was wondering if i could increase the prius mpg by reflashing the ecu or getting a tune up on it,,,,when i did this for my evo it increased my mpg substantially,,,and i was also wondering what year prius is the best for mpg and i also heard of after 15,000 miles the (break in point) the prius gets better mpg,,,and is there a car that gets better mpg then the prius,,,,,i drive about 40+ a day to work,home and for other stuff,,,