Two Pickups with more similarities, such as the body structure, starting price, height, and maximum occupancy, than differences, like the horsepower, fuel economy, and ground shadow size. First of all, the 2017 Toyota Tundra Regular Cab has bigger and thirstier engine; the 2017 GMC Sierra 1500 Regular Cab gets 4.5 more mpg. And finally, the body structure of 2017 Sierra 1500 Regular Cab is slightly smaller than that of the 2017 Tundra Regular Cab. Among similarities are the body structure, starting price, height, and maximum occupancy.