My understanding is that it's an old myth to baby the engine in the beginning.
You need to gun it whenever you can in the beginning. Just don't get busted by the boys in blue...
I bought my car and there was 37 miles on it. My guess is that all the salesmen got into the car when they got it and I'm sure they played with it. So I'm confident that they punched it quite a few times.
I do feel that breaking in should go beyond the first 20 miles. It's the most critical part, but I think what the manual says is pretty accurate. Beat up on it for at least the first 1000.
Some of you worry way too much about breaking a new car in ... beat the $hit out of it, that's what warranties are for! That's how I broke mine in and it still runs great today and I never had a problem with it. Besides ... How do think people test drive these new cars off the lot? They stomp on it to see what it has, I know I did when I took mine out before I bought it. Chances are if your's was already test driven before you did, you can guarantee it wasn't babied anyway.
break in????
i couldn't laught my azz so hard when some people said "wait until they get broken-in".....
there is no such thing with new engines, like someone else here said, they were run hard before leaving the factory... there is no such thing as a real break-in with new engines, i ran mine like i stole her since i was taking her for a test drive