[jdcorbitt3]

The fuel tank is below the lateral CG. This is a relatively light fuel load. Any decrease will improve acceleration and braking. 70 lb is 3% of the total weight of the car. You will notice it if the change is instantaneous like giving a child a ride. In planes, particularly taking off on a hot day at a high altitude airport like Denver, fuel load may be the difference between going and not going. The fuel load can be as high as 50% of the weight of the aircraft. Burning 1000lb on a 17,000lb plane is the difference between going to 43,000ft and 45,000 ft.
I have had a trip out of Lake Tahoe, where if the temp went from 30°C to 31°C determined whether we could come nonstop back to Florida or have to stop in Reno.
It was takeoff performance based on having an engine failure and climbing out on one engine.
The bottom line is the hotter it is and the higher you drive the more that 70lb is going to affect your performance.

John