The way I see it, sharing a full save is like being given a Need for Speed: Underground or Most Wanted save with all the cars. You will have all the cars, yes, and one, at least, not tuned by you or to your liking (in the case of HI the character will not have your name) but you will miss all the content of the game. you will be able to repeat races, but you will miss all the non-repeatable events