[Mach1_8]

Hello all. I've been lurking here for ages, doing my (obsessive) research for an upcoming purchase. Now that the car is inbound, I find myself with a whacky question that I haven't been able to find the answer to, at least not explicitly via web search or searching the forum threads. Hopefully someone here has done something similar and can help me out.

I will be taking delivery of a 2014 320i that I purchased via the the military overseas program. I can get European maps installed if I want, but I will have to get US maps installed on my own dime when I return. During my research I found that it appears pretty simple to buy map upgrades, get a code and basically conduct map upgrades DIY. My question is will this procedure work if there are European maps already loaded or will I need to take to car in to the dealer for some sort of system clearing before loading new maps? Seems like a silly question, but I'm only over here for a few more months, so if it's going to be a pain I may just have them load US maps before delivery and use my phone for the remainder of my tour. Many thanks for your time.