Originally Posted by
BarracksSi
The thing about car brake "upgrades" -- specifically most big brake kits, which I think is what was used in those 350Zs -- is that they upset the brake balance of the car. If you put bigger brakes in front, they're going to lock up the tires with less brake line pressure, which means that there's also less pressure going to the unmodified rear brakes -- which results in longer stopping distances.
This isn't necessarily true. Most good brake kits will come with an adjustable proportioning valve (unless you're talking about crap ebay "big brake" kits?). Also, larger rotors and calipers are mainly added for greater surface area [cooling abilities]. Braking force is more of a function of piston exertion and pad material.
Secondly, the vast majority of your braking is done by the front tires, so unless for some reason you manage to lock the back tires up before the front tires (the opposite problem my miata has) bigger front brakes will generally result in a
shorter stopping distance, especially from high speeds. Where poor brake balance really becomes a problem, is when you try to trail brake or need to modulate the brakes in anything but a straight line (it happens).
Bikes vs. cars aren't always a good comparison.
Also FWIW tires make more of a difference to your stopping distance than your brake setup.