My 6MT BRZ for its first two years (16k miles, <14% highway, mostly short trips in western MA):
- 25.1 MPG = Average in Winter (lots of donuts, warming up)
- 28.8 MPG = Average in Spring/Summer/Fall (includes track day, many fun drives)
- 27.4 MPG = Average overall (seems to average 26-27 MPG in-town and 32-35 MPG highway)
- Fuel log
I averaged ~18 MPG in my RX8, and ~22 MPG in my 2.0L WRX with similar driving cycle.