I’ve used non-local dealers before / and dealers I hadn’t bought from. Heck, I used to live next to a dealer for a few years and their service dept. did all sorts of work for me - some of it aftermarket parts installs, track prep, and they were really great about it. I had a guy who pretty much always worked on my car, and the service advisor was also very good. With the aftermarket stuff I just asked them for a “Go / no-go” as to whether they would do it. Most they did, but a couple things they weren’t comfortable with due to the complexity. My guy could do it - his dragster was frequently in back of the service bays, but some things the dealer didn’t want to get into. I understood and thought they were pretty good about it rather than just blindly saying yes and then ******** it up. I did eventually become a customer, buying my Lightning from them.
As with many things in life, being on good terms with the staff who work on your stuff is something that never hurts.