If you're talking about drag racing...the unsprung weight of the front wheels is not as import as the sprung weight of the whole front end. The reason why is that it is the sprung weight that will be moving (up) first to shift the weight back onto the rear suspension. The weight of the front wheels really won't be a factor until the car has enough front end lift that it reaches the travel limit of the front suspension and tries to lift the front tires off of the ground. The weight of the front bumper will have a much bigger impact on weight transfer than the weight of the front wheels/tires.
