I recently put 4:10's in mine. Gas mileage if i baby it is 18-19 if i hammer on it all the time it's 16-17. Highway was 25-26 at 70 mph it was at about 2400 rpm. So far it's been the best upgrade that i have made. With the fluid and all i paid $300 to have mine installed. Well worth it. I drive mine daily and have seen no adverse effects.