I'm sure that modern engines are actually now "run in" before they come into contact with the car.
This is what i was told when i bought my Alfa new 2 years ago, The salesman actually said that if you drove the car normal from the word go you'd end up with a looser engine quicker therefore reap the performance benefits.
I however kept the revs down for the first 1k of driving. My thought is that if your going to keep the car until its high in mileage (which the Alfa will be due to commuting) then break it in gentle, If your getting rid after 3 years and 30k then drive it normal as it'll loosen up quicker.
Think the instruction manual will detail the run in but it will be certain revs (5000rpm?) and not heavy throttle for first 600-1000 miles and possibly oil change after. As macdaddy says though, most modern engines have very tight tolerances and theoretically don't need running in but not sure I could be that sadistic with my new £30k motor!
I know of a MKV that has had very hard life from the word go, never run in, and it flies. Completely standard its really quick so god only knows what would happen if it was tuned.
At Porsche, the engine is dynoed before being installed in the car and if it doesn't make the right power, its sent back to be completely rebuilt. That means its been on its rev limiter for the first couple if miles of its life and they tend not to suffer as a consquence!
Well having had 3 new engines in the .:R, i should know about running in doesn't really matter about keeping the revs down, use the whole range, but don't do it by thrashing it, use its steadily if that makes sence. Do this this for the first 500 miles then start to increase things a tad. But once reached the 1k mark, oil and filter change the give her hell as this cars need to be driven hard to get any benefit out of them. As Dan said i know the .:R he is talking about and that flies, really is quick. Thats never had any issues. Basically don't be shy with her:151:
Difference with Porsche doing that is that each engine is assembled by one person so they can be held responsible if it doesn't make the right numbers/goes pop on the engine dyno. Makes people proud of their work and so they put 100% in.
VW on the otherhand, use monkeys on certain days to assemble the whole car and its a lottery as to which day your car was built as to whether it was the monkeys or , the oddly more useless, VW techs that put it together. Jimmy's first 2 engines were Tech assembled and they went bang in a big way. The 3rd one, which seems to be working properly, was monkey built.
I'm a full believer in the harder you push an engine when its new the better it will be, this deffinately works with our machines at work, we get new tractors every year and the more hard work you give them from the word go the better they are and I dont see why this shouldn't work with cars:151: