NA geared car will be faster if both TT and NA geared cars were in the same gear. However, NA gears are shorter and because of this there will be a speed range in which the TT geared car could be operated in a lower gear than the NA geared car. In this speed range the TT geared car will be faster. Read this twice.
NA geared cars lose traction at lower engine torque than TT geared cars. What this means is that the TT geared cars utilize the engine torque better.
By cruising, I mean steady speed of 60-80mph obviously. At at that steady speed, NA gearing will degrade mileage most likely.
