I never knew the GT has different gearing, thought it was always the same engine and transmission. I am pleasantly surprised by my GTP getting 31 MPG but allot of that depends on road conditions, weather, and such. I usually only take it out during nice weather and the only big mileage test I did was when I drove it from Washington DC to Marion IL and it got 28.5 MPG but that was snowy weather, bad roads and the air filter was clogged. That is when I first purchased it. When I drive to Paducah KY from Marion which is 50 miles each way, I average 31 MPG
