I'm still kicking myself for not buying this ERA

[ERA Chas]

Originally Posted by patrickt

But you know, I wouldn't do anything on your car until you've put a good 500 miles on it. And nice, gentle, baby miles at that, none of this "drive it like you stole it" crap. Baby the first 500.

Let me disabuse you of this myth so you stop passing it to newbs like you know what you're talking about.
In the case of engines that are dynoed before installation, that is not needed at all. It's already been broken-in and tested to its RPM limits on the dyno. Look at Lipton's thread by Brent and see 7000RPM in the first 1/2 hour of its life. If an engine is installed that has not been run-in or tested then a dyno regimen of 20 minutes at 1800-2500 RPM followed by leak checks, spring changes, adjustments and oil change in the car is sufficient.
If you mean the entire chassis and drivetrain, 500 miles are not needed to mate new parts in the trans, rear or clutch.
What is of paramount importance is that the engine and drivetrain be brought to operating temps before any performance driving. And that's true for the life of the components.
If you're really talking about a new owner's learning curve with high-power, short wheelbase cars then you're correct. They need to work into the car's envelope carefully regardless of the other high performance experience they may have had.