Goto the dealer or an authorized shop, only if its on a lease.
What happens is when you give it in at the end of the term, a lot of times you the dealer can spot a bad paint job, and BMW refers to it as "Orange Peel" then they want you to cover a new coat of paint by an authorized dealer.
Also if you take it to an authorized dealer the work is guaranteed, you show them the paper and they can't hassle you about the "Orange Peel" as their own guys did it.
I think the price difference when that happened to me was 1K at the dealer, vs 250$ at my friends shop
I chose my friends, lol - but let me tell you that was the start of the end for the car.