I’ll add to Flu’s comments that not only should you not take a nice(r) car to Costco for tire work, that you should not take any car to Costco (I used Mission Valley Costco) for tire work. I took my ’96 Geo Prism (not a “nicer” care by most definitions, but runs great!) for 4 new tires a few years back. Everything went great and I drove the 2 miles back home. The next morning, not 1 but 2 tires were completely flat. To cut a long story short, they had not seated the tires well on the rims. The manager, a ~50yr old like myself blamed it on two things:
1) my old rusted rims
2) dumb 18 yr old kids he hires
He was very nice and fixed everything, but it cost me half a day getting it sorted. I also had to replace one of the wheel studs recently because it was stripped. It’s a little hard to blame Costco definitely for this one (things wear out), but they are the main ones that have taken the wheels on and off.
I also agree that they are great for lots of other things. I’m tending to shy away from them for appliances however. I’m beginning to wonder if they get lower quality lots. I notice that I have quite a few problems with vacuums, electronics, washers, dryers from Costco. On the plus side, they have a very generous return policy.
Best of luck with your BMW. If you get sick of it and want to trade for my Geo Prism feel free to msg me.