So far the Insideline fuel economy is somewhat similar between their CVT Impreza Sport and their manual FR-S. Although the EPA rates the combined fuel economy 5 MPG higher for the Impreza, their fuel economy is separated by no more than 1.3 MPG in the first few thousand miles.
http://blogs.insideline.com/roadtest...june-2012.html
http://www.fueleconomy.gov/feg/Find....n=sbs&id=31829
http://www.fueleconomy.gov/feg/Find....n=sbs&id=32309