The dealers here in Dubai and Abu Dhabi as well as the BMW body shop are all telling me that any modification from exhaust to wheels to body kits will void the warranty of anything related to the part installed. So if I install exhaust they say that my Engine (Everything under the hood) and a few other stuff will be voided. With wheels, everything under the car is voided.

Anyone know something I could tell them to get them to shut up, install it, and let me keep my warranty?

I moved from CA to Dubai, and I am pretty sure there is no rule like this in the US. Could someone confirm this?