[HennarotM3]

I haven't taken my car in for service at Passport yet, but in my brief conversations with the SAs and managers they seem pretty reasonable about mods. They are the ones who alerted me to e90post in the first place and even offered to do the golf tee mod for me (I declined).

Look, no dealership SHOULD look the other way when an aftermarket part damages the car - they're fiduciaries to BMW, not you. What you want to avoid is dealerships who go out of their way to blame routine things on modifications.

I would just say be reasonable in what you expect the dealership to be cool with. When push comes to shove, it's "you break it, you buy it" no matter which dealership you frequent. And I think it should be that way.