I kinda skimmed the article. Nothing really new for me. Weight savings means less to move up and down, accelerate or decelerate and makes a difference. How much difference is the debate. The closer the weight to the center of rotation the less of a problem. If you want a real world example to think about go back to the mid 70's when it was all about fuel milage. The cars that did the best had 13" wheels and tiny tires (yes they were light with tiny engines too). Less friction, weight, etc. For racing what matters depends on the car. How heavy it is, how much power, how fast the track. For light lower power cars it's often better to have less tire for aero and weight reasons. Heavy higher power cars need all the rubber they can get even if it's heavy. The taller the tire (weight farther away from center) the more important the weight of the tire itself. I've used my stock rims with both light and heavy tires. I've used my Forgestar's with both medium and heavy tires. For me what's important is cornering grip level. The unsprung weight makes more of a difference in how the car handles than how fast it goes but it does make a difference

As far as big lightweight brakes. They stop better but mostly because it takes less pedal pressure to achieve the same braking force which, for me, makes it easier to threshold brake. I can say from experience that being close to loosing traction under braking will stop shorter than engaging ABS. The most important braking component is the tires and next is drivers ability to modulate the pedal. Actually the fastest stops are ever so slightly slipping. The larger components of a BBK have greater capacity to absorb and radiate heat. It keeps the fluid and wheel bearings cooler so braking is more consistent and reliable. With stock brakes I was constantly bleeding them and with the BBK I'm not obligated to bleed them between heats. I always bleed them before an event however.

Unsprung weight makes a difference, just not enough to easily be felt by the buttaccelarometer or buttdecelarometer. I'm not disappointed in the lightweight parts I've purchased but the price of them is out of proportion with the gains. By far the greatest increase in speed at the track was from wider wheels and tires. (corner grip) More rubber means faster corner speeds, lower stopping distances and traction for acceleration.

I could go on but I'm confusing myself.

Les