Is a spare tire required to pass inspection or just in case of a flat? I have seen tire repair kits used in place of a spare tire- sealant and compressor. In fact I think the RWD Q60 does this.
I hear what you say about run flat tires and tight suspension but if all Q60 ride like mine no one would ever buy one if they test drive the car before buying. I made a mistake, my test drive was on one with regular tires and my lack of knowledge and experience with run flats I just assumed they were the same or similar ride. I know I would not have bought my car if I test drove it, bad mistake on my part.
I am really surprised I don't see more on this forum about this issue. My friends that have ridden with me notice the rough ride and noise right away and politely comment on it. Maybe I just have something wrong but I had a dealer tech ride with me, all he could say was "that's normal, that's normal etc".