Nowadays, alot of things are control by chips sets.... the run in is more for the chips... of cos a bit for the engine too. engine normally dun spoil easily and can last for a prolong duration like for more than ten yrs.... However it is best to do as told by the instruction manual as they are the ones who produced the cars and the ones who design the structure of the car.... they will know wat is best for the car....
alot of things like nv warm up the car, using of low RON fuels, using of cheap engine oil WILL not affect the performance or main components in the short run... however the damage may be there in the long run....

So unless u are thinking of changing cars every 5 yrs or so.... the best is to do wat that is being told.....