Just a little update:
I filled up my car last night and calculated my MPG..... 46.14 US MPG, with a distance of 394 mi. and used 8.539 gallons.
Previous fill ups without block heater = 41.45 US MPG, 43.12 US MPG, and 43.33 US MPG.
MY GASLOG
Proof that having a block heater installed will help improve FE.
The average temp since my last fill up has been 22°F that is with one day of 42°F high (freak thing) and then a cold few days from -15°F (ironically that was just a day after the 42° day).