I have HUGE disagreements with PPF.....and I've been using it back when 3M was king.

Aesthestics, clarity, protection. It's a no brainer the lowers, door mirrors or stuff that will oxidize, no matter how much you polish/seal/coat on. On the E53, due to the sill mouldings, it is a no brainer to wrap the lower doors.

Just do keep in mind, for custom installs, these guys are literally taking Xacto knives and are are scoring the film - more often, they score the film right off the paint. ~~you don't see the mistakes as the film masks it~~, but sometimes, they score right into the paint. You will never be the wiser, until you remove the film due to age, etc. Just fwiw.