Great car !
Re the 3m, it is a compromise between coverage and visibility. I opted to have the lower front bumper covered (up to the bottom of the lights), but opted to leave the bonnet - which would have resulted in a visible line across it. Also had the wheel arches, fenders and door mirrors covered. You can't see it at all.
The extent to which it's needed depends on the roads you drive on and in particular the amounts of grit. I have friends (around London) with X5 M sports who haven't had any chipping (and no 3m fitted) as there's pretty much no grit on our roads. I however decided to play it safe particularly as I'm off to the Alps this winter.