FWIW, I just flat out REMOVED the spare tire carrier tray and spare tire this year, and I will probably remove the metal tray carrier later. It was the original tire and I really didn't trust it for actually working as intended for the past 10 years, and I always carried around: a battery powered air compressor, two types of tire plugs. and a AAA road service card. I was getting tired of removing and replacing the spare tire tray before and after every autox this year - that was the final straw.
My thinking is, if I get a flat tire or come back to my car and a tire is flat, I'll inflate it and see how quickly is loses air and if I can easily drive to the nearest tire repair shop I'll do that, OR if I can see an obvious nail or hole that I can repair on the spot to get to a tire replace place I'll do that, and if all else fails, AAA will flatbed my car to a tire shop. Honestly, because the flat full size tire won't fit in the trunk anyway once I mount the spare, I was unlikely to use the spare anyway.
And before you say how insane this all is, remember that the M Coupe and M Roadster didn't have spare tires at all, and came with an electric tire inflator, a can of fix-a-flat, and toll free number for roadservice from BMW.