That first article on "break-in secrets" is just snake oil. No engine ever suffered because it was not hammered from new. Some cars are never hammered in their lives and the piston rings do not magically disintegrate or fail more early - if ever.
The article on bedding in brakes is bunkum too since bedding in brakes depends entirely on what discs and pads you're using and what that particular manufacturer recommends. Different pad materials and different disc materials require different treatments
But it's all cack anyway because you can just get in your new 3 series and drive it
The only thing I'd take care of it letting the discs go through a few heat cycles before taking the car on a track or doing any really spirited driving otherwise you'll just warp them. But then if you're doing that you should be using uprated brakes anyway
Get in it, love it, drive it.
Don't worry about it