[RedDevil]

Originally Posted by BabyDiesel

It should be noted that 1 pound of rotational mass is equivalent to 8 pounds of car mass. In kilos, 0.5 kg RM = 4 kg

In essence, it would make the car accelerate as if he had lost around 64 pounds of car weight.

Sorry, but that is not true, not for wheels anyway.
I was hoping to find a simple equation but wikipedia is no fun: https://en.wikipedia.org/wiki/Rotational_energy and https://en.wikipedia.org/wiki/Rigid_rotor...
Equations galore, but not simple.

You can simplify the model by substituting the whole wheel with a point mass.
The energy contained by the rotational mass is equivalent to the speed with what that mass moves along its trajectory; radius and the speed of the whole system are irrelevant, e.g. the effect is the same with big and small wheels, and the rotational energy in the system is independent of the movement; it would be just the same if it were spinning its wheels on ice.

The fastest moving part of the wheel is the tire thread; it rotates at the same speed as the car, so it has the same momentum. It doubles the total inertia, once for its general movement, once for its rotation.
The rim is closer to the center of rotation so it contributes less to the total inertia.
In all, a wheel will add about 1 2/3 of its weight to the total inertia.
The engine and gearbox parts may rotate much more quickly; they can easily add more than their weight in rotational mass.

However, wheel weight is unsprung weight. On rough roads extra wheel weight adds a lot to the rolling resistance, as every bump in the road will have to move more mass out of the way.
Under the right conditions extra unsprung weight can increase the resistance 8 times more than sprung weight, or more. For that reason alone light wheels are recommendable.